Good News for Late Fliers on the Benefits of Bumping : Airlines: Your flight is overbooked? If you’re patient and ask the right questions, you may soon be sitting pretty.

It’s the height of holiday madness and you’re headed for the airport. Fighting the traffic, you reach the terminal just in time--only to find that the airline has oversold your flight. You end up getting bumped from the plane and left behind to wait for a later flight--maybe a much later one.

This may sound like bad news in the midst of the year-end festivities, but to some passengers it’s actually good news. Some people are eager to be bumped so they can collect denied-boarding compensation in the form of cash, free airline tickets or cash vouchers that can be used to buy tickets. On some flights these days, passengers actually compete to give up their seats for freebies.

For these eager beavers, the holiday travel season is prime time because so many people are flying, according to Tom Parsons, editor of Best Fares Discount Travel magazine. A monthly, it tracks air fare, lodging and car rental bargains around the nation.

Parsons has compiled a list of steps that could boost your chances of getting bumped profitably. If you do give up your seat, of course, you can expect to arrive at your destination at least an hour or two late--and maybe more. On the other hand, you also could be carrying extra cash to pay the holiday bills or a ticket for a trip in the months ahead.

But for other travelers, getting bumped may be a hassle they hope to avoid, especially if they are on a tight schedule. Overbooking is not illegal, and most airlines overbook their scheduled flights, says the Department of Transportation. The agency has just issued a revised edition--the first update in nine years--of “Fly-Rights,” its consumer guide to air travel. The guide explains how best to avoid getting bumped and details your rights if you are denied boarding.

Airlines overbook because they expect a percentage of ticket-holders to be “no-shows,” says DOT, and the carriers don’t want to fly with empty seats that could be sold profitably.

In the three-month period from April through June, the nine major U.S. airlines bumped more than 178,000 passengers from oversold flights, according to DOT’s latest statistics. All but about 12,500 of them agreed to be bumped in exchange for compensation. The rest lost their seats involuntarily. They also were entitled to compensation, provided they had complied with airline check-in policies and other restrictions.

Whenever a flight has been oversold, federal rules require the airlines first ask for volunteers to give up their seats before anyone is bumped involuntarily. On most flights, a few passengers usually have the flexibility in their schedules and are willing--for a price--to catch a later flight. DOT does not specify how much volunteers should be paid for being bumped, leaving it up to the carrier and the passenger to negotiate mutually acceptable compensation.

In practice, a gate agent boarding passengers usually makes an opening offer. If there are no takers, the offer may be raised until someone accepts. Compensation can be cash, free tickets or other benefits.

There are hazards in voluntary bumping, as “Fly-Rights” points out. Make sure the airline can confirm a seat on a later flight, the guide advises. If you are put on standby for another flight that is full, “you could be stranded.”

If you face a long wait, ask if the airline will pay for your meals, a phone call or a hotel room. If not, these expenses could end up costing you more than you got for volunteering. If you are offered a free ticket, determine if any restrictions apply.

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But if you want to boost your chances of getting bumped--if this is what you want--consider these steps:

* Before leaving home, check with the carrier you will be flying with to find out if your flight is full or near full. If it is expected to be half empty, there is little likelihood you will be bumped, and the steps that follow are not worth your while. But remember, stormy winter weather can play havoc with airline schedules, and a half-empty plane can easily fill with stragglers connecting from delayed flights.

* Be sure to carry reading or work material: You may have to amuse yourself for hours at the airport.

* Inform family and friends at your destination of your plans, so they are aware you may be delayed.

* Plan to arrive at the airport at least 90 minutes to two hours before flight time, advises Parsons. You want to be first in line at the departure gate when it opens for check-in so you can be the first to volunteer.

* If the plane is oversold, bargain for a round-trip ticket, Parsons says. It may be more valuable than the $200 or $400 maximum the carrier is willing to offer. Be sure the airline confirms a seat for you on one of its later flights or on a flight on a competing carrier.

* If you are delayed by more than two hours, says Parsons, ask the gate agent for a free phone call to keep family and friends up to date. If you are hungry, ask for a voucher for a free meal. The airline is not obligated to provide either, but it doesn’t hurt to ask.

As a final note, Parsons suggests that if you get bumped once during a busy holiday season, it might happen again. If the new flight on which you are booked with a confirmed seat is also oversold, he says, volunteer again to be bumped from it. “You may end up with another free ticket.”

Christopher Reynolds is on assignment.