For a few moments last month, a crowded gate at the San Juan, Puerto Rico, airport turned into an auction in reverse.
A flight to New York City was overbooked, and an airline representative was offering $100 vouchers to passengers who would agree to take the next available flight. Nobody took the deal. The amount offered went up and up, all the way to an impressive $600, before four travelers agreed to stay.
"Dollar signs lit up in people's eyes," recalls David Lytle, editorial director of the travel website frommers.com, whose flight was leaving from a nearby gate.
There must have been worry, too. If no one gave up his or her seat, four passengers would have faced one of the most dreaded hassles in all of air travel - being involuntarily bumped and, at least for a time, stranded.
Thanks to airlines eager to fill every seat, the number of bumpees is rising. Eighteen US carriers involuntarily bumped 1.33 out of every 10,000 passengers during the first six months of this year, up from 1.21 in 2006, according to federal statistics.
The rate was just .72 passengers per 10,000 in 2002, during the travel slump that followed 9/11.
In the grander scheme of air travel in the United States, these numbers are minuscule. Airlines are much more likely to lose your luggage than bump you from a flight. (For every 10,000 airline passengers in the first six months of this year, 73 bags were reported lost, stolen, or damaged.) Even so, the delays are yet another aggravation for passengers already coping with jampacked planes.
It may seem illogical that airlines sell more seats than they have. Movie theaters, by contrast, don't overbook: If you buy a seat, it's yours.
The difference is that tickets for airlines are infinitely changeable while a movie ticket for, say, 4:15 p.m. can't be changed, says Peter Belobaba, who studies the airline industry at MIT in Cambridge, Mass. Some plane tickets can be refunded even if you don't take the flight, and others can be changed at the last minute without a penalty, especially if the ticket cost a lot of money.
"The airlines use complex statistical models to predict how many people are going to show up for a given flight," says Steve Call, director of a travel and tourism degree program Ohio University-Ironton. "Over the years, they've determined they need to oversell a flight by X amount of seats because there will be no-shows."
Cash for those bumped involuntarily
But sometimes there are more people than seats, and airline representatives start offering vouchers for future travel. If no one accepts, airlines will kick one or more passengers off the flight, rebook them if possible, and pay them up to $200 or $400 in cash if their landing time is delayed more than an hour.
Credit a certain consumer advocate for the payment scheme. "Some airline made the mistake of involuntarily denying [a seat to] Ralph Nader in the early 1970s," says Mr. Belobaba. "He sued. That's how this whole policy came about."
There may be some good news in the wings: The US Department of Transportation is considering whether to raise the amount of cash that passengers receive if they're bumped involuntarily. Under one proposal, involuntary bumpees would be due up to $1,248.
Cash, of course, won't buy every passenger's happiness, especially if they're in danger of missing a wedding or a World Series. If you don't want to be bumped, there are some nearly surefire ways to avoid it.
"Make sure you have a seat assignment," advises Belobaba, "and get to the airport on time. It's always the laggards and those who don't pay attention to what they're doing who get involuntarily bumped."
Many airlines will allow you to go online and check how full a flight is; that could help you avoid a chronically overbooked flight. And Belobaba suggests that passengers remember the old adage: "You get what you pay for."
Financially pressed airlines going further to fill all of their flights
The involuntary bumping rate last year was 1.01 in every 10,000 passengers -- that's a 15 percent increase from the 0.88 rate in 2005.
This is the first penalty issued by the Department against an airline for failing to disclose fees or other restrictions on the use of oversales vouchers.
The rules offer a blanket of consumer protections, including increasing compensation for passengers involuntarily bumped from flights.