I’M not the most talkative person on airplanes. I used to be much friendlier, but an inevitable question is, “What do you do?” When I say, “I’m a professor of computer science,” I always wind up doing a lot of free consulting.

I swear every seatmate for a while had computer problems. While I’ve occasionally been successful at helping people fix a problem, usually people end up disappointed and tell me, “That’s just what the guy on the phone said.”

Years ago, most of the questions were about lost documents. Now, people are more worried about computer security. They want to know if they have something “bad” on their computer. My general answer is, “You do, but don’t worry about it.”

Recently, when seatmates ask me what I do for a living I’ve started saying I’m a Web scientist, an emerging area of computing that I’ve been involved in for the last few years. Most people are too embarrassed to say they don’t know what that means, so the conversation quickly turns to more friendly topics.

My most frustrating experience this summer was getting caught in the United Airlines computer failure on June 17. My flight was on the tarmac in a delay situation, so I called the airline from the plane and got booked standby on the next flight.

While we were on the tarmac, the computers crashed. It’s not as if I could say “Let me fix them.” I probably couldn’t. So we sat for a couple of hours until they got us off our now-canceled flight.

The flight on which I was supposedly booked for standby was very late. But since the computers were still down, they didn’t have a standby list. I was not one of the lucky few who actually yelled loudly enough to be put on that plane.

But several other people were in the same situation, so we rented a car at 1 a.m. and drove the eight hours home.

My airport vice for a year or so is using Twitter to post about my flight delays. Two interesting things have happened. I’ve discovered a community of frequent fliers who also publicize their problems. Misery loves company, and we’re starting to get to know each other’s flight tricks.

The second is that the airlines actually listen. I even received a Twitter direct message from United asking me to let them know my flight numbers when my plane is delayed or canceled. I’m not sure what they’ll do, but it does show the power of social media.

I recently faced a new dilemma. I was using an online boarding pass, and I needed the encoding of the information on my phone. After a flight from Europe and a couple of hours sitting in the airport, I wound up in a situation where my flight was in a rolling delay. Every 15 minutes, the departure time was moved up. I would get a phone call from the airlines letting me know that.

I watched my phone battery getting lower and lower. By the time my flight was finally ready to board, my phone was on fumes and there was no one who could reprint a boarding pass. No phone, no boarding pass, no flight.

I got lucky. My gate agent had a socket at his station and I had a charge cord with me. I talked him into letting me plug into it to show him the boarding pass.

I love technology, but, even I, a professor of Web science, have gone back to printing my boarding pass. Just in case.

THE older I get, the longer the list of people I don’t want to talk to.

So let’s just say that I made note of recent comments by John S. Pistole, the head of the Transportation Security Administration, that his agency planned to “upgrade” an existing program in which security officers engage selected passengers in conversation near airport checkpoints.

Mr. Pistole said that expanding the so-called behavior detection program now in place at 161 airports would allow officers to “have more interaction” with more passengers. The idea, loosely based on well-known Israeli aviation security procedures, is that trained agents try to detect behavioral signs indicating potential threats.

Now, most of my interactions at checkpoints have been pleasant. But I’d just as soon get through security as quickly as possible. The only verbal interaction I welcome is the one that occurs after takeoff, when a flight attendant comes by to ask, “Would you like a beverage, sir?”

I’m open to alternatives, though. And as it turns out, the security agency is, too.

Expanding the behavior program is one aspect of the T.S.A.’s initiative to focus more on what it calls risk-based intelligence — to provide smarter overall security while decreasing the grim drudgery of the search for mere things at the checkpoint among the undifferentiated mass of passengers.

As part of that thinking, the agency is also starting tests at four airports this fall of a new so-called trusted traveler program that would, if adopted, offer expedited screening for qualified passengers who agree to provide personal information for a background check before flying. At the same time, the agency is giving a tentative nod to the rebirth of an old security program that ran aground without firm T.S.A. support in 2009 — Clear.

Yes, Clear is back, though only at two airports right now. You remember Clear, the private program based primarily on issuing biometrically encoded identity cards and giving its members special security lanes at airports. Clear’s spiffy blue and white kiosks had expanded into more than 20 airports before it shut down abruptly in 2009, abandoning about 150,000 members who had paid up to $199 for their annual ID cards.

Under new management, Clear tiptoed back into operation last November. It is now operated by Alclear, a privately held company that bought Clear’s assets from its previous owner, Verified Identity Pass, at bankruptcy auction.

The old Clear foundered for various reasons, including heavy debt. But officials at the T.S.A. also told me privately on numerous occasions that they were reluctant to incorporate Clear in the security system as a real partner for various reasons. So the old Clear, despite those biometric-scanning kiosks, operated just as a fast-track lane. Once they passed through the Clear kiosk, members merely proceeded to the regular T.S.A. checkpoint, where they had to show a government-issued photo identification and were treated exactly like everyone else.

The new Clear, which costs $179 a year, is now operating only at airports in Denver and Orlando, Fla., but the company plans significant expansion on a bet that the T.S.A. will accept it as a partner in the agency’s efforts to focus more on risk-based security intelligence.

It undoubtedly helps that the management of the new Clear includes executives with government security experience. The president, J. Bennet Waters, for example, is a former deputy assistant administrator at the T.S.A. and, more recently, was the chief operating officer at the Chertoff Group, the security consulting firm founded by Michael Chertoff. Mr. Chertoff, the former homeland security secretary, is on the board of the new Clear.

It isn’t yet apparent exactly how the new Clear and its various likely competitors will fit into Mr. Pistole’s plans. Nor is it clear how trusted traveler proposals can address concerns about the obvious faults in the system — most recently exemplified by the Army private, Naser Abdo, charged with plotting a terrorist attack on Fort Hood in Texas. As a soldier, Private Abdo, of course, probably would have qualified as a trusted traveler.

There is no such thing as 100 percent security, of course. Mr. Waters said that ironclad identity verification, coupled with background checks by private companies, would be one important layer in a multilayered system.

“We want to be a partner providing an enabling technology that leverages the power of biometrics and commercial data and technology to enable John Pistole’s vision for risk-based screening,” he said, “with high confidence that we have determined who is low risk and who may be higher risk.”

The discussions about hotel safety recently have centered on what happened in a suite at the Sofitel in New York between Dominique Strauss-Kahn, the former head of the International Monetary Fund, and a hotel maid.

But business travelers can fall victim to attacks, too, by intruders, hotel staff, even other guests. Most often, the victims are women.

Paxton Quigley, a women’s safety consultant in New York and author of “Not an Easy Target” (Fireside, 1995), said most women business travelers were “just beginning to learn how unsafe they can be, especially in airports and planes, hotels, walking on streets in cities that they don’t know and in convention settings.” Conventions, she said, leave women particularly vulnerable because “they’re wearing name badges and are telling people where they are staying.”

Jeannette Duwe said she was staying at a hotel in Reno, Nev., while traveling for the grocery store chain Albertsons when she was attacked in 2002. She was working late on news releases in the business center when a man pried the door open and began bothering her. “I asked him to leave a couple times,” she said, adding that she “made the mistake of turning my back to him, which is when he hit the lights and attacked me.”

Eight weeks pregnant at the time, she said she worried that no one could hear her scream, but, “Something spooked him after a couple minutes and he ran off.” She immediately called the front desk for help.

Travelers can take several steps to protect themselves, said Marybeth Bond, a women’s travel expert in San Francisco who runs www.gutsytraveler.com and has written several National Geographic women’s travel books. Women need to “trust their instincts,” she said, if a situation seems awry. When hotel employees make deliveries, she said, travelers should either leave the door fully open or say, “I’ll take it from here — you don’t need to come into the room.” Ms. Bond carries a rubber doorstopper to jam under her hotel door and says she makes sure any adjoining hotel room doors are locked.

Ms. Bond also said hotel bars could be problematic. “Men are always hanging out there looking for something,” she said. “I love the hotels where I can order a glass of wine and have it brought up to the room. Ask for a woman to bring it.” In this way, she said, “You set the tone, and then they know you are taking control of the situation.”

Hotel bars can be relaxed settings for meeting other business travelers. But Ms. Bond said women should be aware that date rape drugs could be placed into a drink; she recommended coasters from Drink Safe Technologies, which detect some of these drugs.

She added that if consensual sex occurs, “When someone is in your room, lock up your stuff.”

Trouble often starts when a traveler allows someone in a hotel room, said Joe A. McInerney, chief executive of the American Hotel and Lodging Association, an industry group. “Very few things that happen in a guest room would have happened if the guest did not let the person in,” he said.

Hotel lobbies have also become popular gathering spots, and that, too, can spell trouble. “The lobby is becoming a place for young people to be social,” Mr. McInerney said. “We used to call them ‘lobby lizards’ in the 1920s — people just hanging out in hotel lobbies. Now, it’s back with social networking.” That, he said, “is how they do things,” he added, “and that can be a problem.”

Mr. McInerney noted a couple of other highly publicized sex cases involving hotels. One was the rape of the singer Connie Francis in 1974. Her lawsuit against the hotel led to industrywide security changes. Another he cited was the 1992 rape of Desiree Washington, a contestant in the Miss Black America pageant in Indianapolis, by the boxer Mike Tyson. After that incident, Mr. McInerney said, the hotel association began posting guidelines, available on its Web site, to help prevent assaults.

Men can be victims, too. A well-publicized case was the murder in January of the Portuguese journalist Carlos Castro in New York. His companion, Renato Seabra, a male model, was charged.

“On a crime of passion, there is really nothing you can do,” Mr. McInerney said, but there is a need to “educate people that you do the same things” for both sexes regarding safety.

While business travelers may worry about strangers, Stephen Barth, the founder of hospitalitylawyer.com and a professor of hotel law at the University of Houston, said co-workers present risks, too. “People are normal until they check into a hotel room,” he said, adding, “The entire duty of care that companies have for their employees, such as harassment policies, still apply when traveling with another employee.”

Mr. Barth said it was once common practice to give out the hotel room numbers of guests when outsiders called. This method was used in 2009 by a stalker, Michael David Barrett, to locate the room where an ESPN sportscaster, Erin Andrews, was staying. He secretly videotaped her through a hotel door peephole.

While hotels generally no longer give out room numbers, Mr. Barth said the same information still could be found on room service door tags and gym sign-in sheets.

Most incidents in hotels are not widely reported, said Ms. Bond, the women’s travel expert.

Ms. Duwe, the 2002 hotel attack victim, who now runs her own public relations company in Idaho, is a case in point. “I don’t think the attack hit the news because it wasn’t severe enough,” she said. She said she later took kick-boxing classes to protect herself. Still, she said, “When you’re in the business center and someone cuts the light out and hits you from behind and you’re in flip-flops, it’s just an all-around bad situation.”

WE do business in 128 countries, and I’ve traveled to almost all of them.

Any country that has a stock exchange is on our radar, even places like the Maldives, where they recently opened an exchange. In the last six weeks I have been to 16 countries and flown more than 40,000 miles. I recently returned from Asia where I visited 10 countries in 14 days. I spend so much time in the seat of an airplane that when I go to the dentist I instinctively look for the seat belt when the chair is reclined.

My son thinks it’s all very glamorous, and he thinks I get to stay in all these luxurious places. He’s wrong.

I was in Ghana several years ago. There was a power shortage, and they had rolling brownouts. I was in the shower and there was no window in the bathroom. The brownout hit, and I could barely get out of the room without hurting myself.

After that, I started carrying a small flashlight and a roll of duct tape with me wherever I go. You never know when you’ll need those things. As a guy who travels a lot, I can tell you duct tape solves a lot of problems.

I love to eat like a local wherever I go. In Bangkok, I eat the street food, and enjoy it. One of my favorite restaurants there features little plastic stools for patrons to sit on. Four people can dine for $15, including tip. It’s not luxurious, but it is great food.

People often ask me if I experience any anti-Americanism. I really haven’t. I am a true believer that no matter where you go, if you treat people with respect, a nice smile and a little bit of charm, they will go out of their way to help you. I have rarely been proven wrong.

I always want to be very respectful of cultural differences, but sometimes those differences can get confusing. On my first trip to Japan, I met with seven Japanese businessmen. The gentleman who arranged the meeting also invited me to dinner that night with the group. At the end of the meeting, they thanked me and said goodbye with no mention of the dinner. I whispered to the person who set up the meeting and asked him about dinner plans. He was quite dismissive and said they were no longer available. I thought I must have offended them and I felt terrible about it. I went to go eat dinner by myself.

Several weeks later my business partner and I received a letter telling us the Japanese businessmen wanted to proceed and partner with us. I was astounded. I really thought I had screwed up. Years later I told the story to an American businessman who lived in Tokyo and was married to a Japanese woman. He explained that the guys I met with probably lived far from the city center and didn’t want to commute home late. Since they had already decided to go forward with us, there was no need to take me to dinner. If they had decided not to do business with us, they would have taken me to dinner so I wouldn’t be offended.

Another time, I was doing some business in Karachi. I found out you could order whiskey through room service. But I was told I had to complete two forms. When the waiter delivered the whiskey, he had the forms with him. One was to certify that I was not a Muslim. No problem. The other was to certify that I was using the whiskey for medicinal purposes only. Well, whiskey can help you relax, so that was no problem either.

Let’s talk about taxes. Wait a second, come back here! I mean airfare taxes.

The subject comes up because of what Congress just did — or, rather, did not do — and what the airlines did in response.

On Friday, Congress failed to approve the extension of a bill to keep the Federal Aviation Administration running. Among other things, that meant the agency no longer had the authority to impose the various federal taxes that airlines add to the price of each ticket.

So as of 12:01 a.m. Saturday, the federal government began losing an estimated $25 million a day in tax revenue.

But did airlines simply pass on this savings to customers?

No, they did not.

Last week, evidently in anticipation of the tax’s expiring, some airlines quietly began raising fares — on average, roughly by the same amount as the federal taxes. Others did the same over the weekend, and most of the rest joined in on Monday.

Alaska Airlines and the discount carrier Spirit Airlines were among the few holdouts, said Rick Seaney, the chief executive of FareCompare.com, which monitors airline fares. In a statement, Spirit Airlines took the opportunity to chide its competitors.

“Spirit is passing along all of these tax-rollback savings to its customers,” it said. “Some carriers have not been so generous and have pocketed the difference in taxes, in the form of higher fares.”

“The consumer should have saved anywhere from $25 to $50 round trip,” Mr. Seaney said. “Instead, it’s a windfall for the airlines.”

But Jean Medina , a spokeswoman for the Air Transport Association , the airline industry trade group, said, “Basically, consumers are now paying the same as they did last week.”

The main federal fare levies that expired are the 7.5 percent excise tax on all domestic tickets, the $3.70 federal charge on each flight segment, and the $16.30 tax on each international arrival and departure.

These taxes cannot be collected again until Congress passes another extension of the legislation that finances the F.A.A. Before Friday, the extension had been stalled repeatedly, and its budget temporarily extended 18 times over the last four years.

The airlines had been raising fares in small increments for much of this year, as fuel costs have stayed high. The last increase, the sixth of the year, came in mid-April.

A report by American Express Global Business Travel, which came out on Monday, found that the average domestic fare paid by clients was 7.5 percent higher this May than last May.

And the latest increase would probably have gone through without much comment had it not coincided with the expiration of the federal taxes.

Airlines have long complained about the burden of taxes and government-imposed fees, which now add up to about $61 on an average $300 fare, according to the Air Transport Association. While airline revenue was 8 percent higher this June than in June 2010 — the 18th consecutive month of year-on-year improvement — growth had been slowed by rising fuel costs, the association said.

None of the airline industry experts I spoke to expected the airlines to roll back the new fare increases once the taxes are reauthorized. But what about the taxes the airlines already collected on tickets bought before Saturday for travel during the tax expiration period?

“Are tax refunds in order?” asked Kevin P. Mitchell, the chairman of the Business Travel Coalition, which represents corporate travel managers. Good question.

There is some rough precedent to indicate what recourse passengers might have. In 1995, airlines collected a federal excise tax for travel bought for 1996, assuming that the tax would be routinely renewed before the end of the year. But Congress didn’t renew the tax until the summer of 1996 and didn’t make the tax retroactive.

The airlines that were sued by customers were not liable, a federal court ruled. They did not pocket any of the money because they had forwarded it all to the government, as required, the court said. Instead, that court and others subsequently ruled that consumers’ main redress was to claim the outlays as losses on their federal tax returns.

The current situation is complicated, of course, because the airlines are not collecting the tax at all, but did collect it on ticket purchases made before Saturday for travel through the period the tax is not in effect.

Airlines are generally keeping their heads down on this. One, JetBlue, publicly addressed the matter on Monday, telling customers that it would accept requests for refunds of taxes already paid, for travel within the next seven days. Possible refunds will be “based on the guidance by the federal government,” JetBlue said. For travel beyond seven days, JetBlue said it would provide more information later.

Virgin America, which joined the fare increase on Monday after holding out all weekend, informed affected customers, “You may be entitled to a tax refund through the Internal Revenue Service.”

The Internal Revenue Service said only that it would “continue to work with the airline industry to address issues relating to the collection and payment of the taxes involved” and would “provide further guidance” soon.

Meanwhile, Michael Boyd, an aviation forecaster with Boyd International Group, said that airlines badly needed more revenue to sustain a degree of profitability. With fares now essentially the same as they were a week ago, the current situation is “a wash for the consumer and a plus for the airlines,” said Mr. Boyd, a persistent critic of federal aviation policies. “At least now we know where the money is going,” he said.