Delta to passengers: What do you want for your seat?

NEW YORK (CNNMoney) -- Delta Air Lines has launched a system for travelers who are willing to get bumped from overbooked flights to auction their seats to the carrier.

"Once you tell us you're interested we'll ask you how much you'd like to receive in travel vouchers in exchange for your flexibility," said Delta (DAL, Fortune 500), in a blog posting that outlines the new deal.

As customers check in, they'll be able to enter the amount of money they want to receive on their voucher for giving up their seat. In the Delta blog, the airlines use a sample offer of $200. Customers could suggest a higher payoff than that, but in any instance could find themselves undercut by another traveler.

Bumping occurs when airlines overbook flights, a common practice in the industry aimed at maximizing capacity on planes. It's based on the assumption that some passengers will miss the flight, leaving empty seats for stand-by customers.

When there are no empty seats, the airlines will seek volunteers to give up their seats in exchange for vouchers. As a last resort, some passengers may be involuntarily bumped.

When customers are involuntarily bumped from flights, Delta provides up to $400 in vouchers for delaying domestic passengers by one or two hours, or from one to four hours for international flights. Delta provides vouchers of up to $800 when involuntarily bumped passengers are delayed by more than two hours for domestic flights, or more than four hours for international.

This is in addition to another change that Delta made in November, allowing customers to volunteer their seats as soon as they check in. Traditionally, Delta and other airlines have asked for volunteers at the gate, shortly before the scheduled boarding, which increases the chances of delaying the flight.

"By soliciting volunteers early, our goal is avoid inconveniencing anyone," said Delta, which recently acquired Northwest Airlines.