United Airlines is testing a new system which would avoid overbooked flights by offering travellers an opportunity to voluntarily be “bumped” up to five days before departure, reports Bloomberg.

The Flex-Schedule Programme would offer travel vouchers worth up to $250 to take a different flight on the same date and from the same airport. The airline, in turn, would be able to sell the traveller’s original seat.

Passengers who book their flights directly with the airline and agree to receive marketing messages from United would receive the offers. The offer could include a downgrade in service level — from Economy Plus to Economy class, for example — but that fact would be disclosed in the offer.

The programme is reflective of a promise made in April by United to “create an automated system for soliciting volunteers to change travel plans.”

“If you can offer a buyout to a customer in advance, everyone will be happier,” said Azim Barodawala, CEO of Volantio, which developed the technology behind United’s Flex-Scheduling.

“For airlines, it represents a release valve—a way to shuffle people around when you’re capacity-constrained. This benefits the customer as well, you’re creating choice for them, and that’s what gets me really excited. [Passengers] get the short stick a lot.”

The airline would benefit by having the ability to sell the passenger’s seat for more money, avoiding much-higher payouts for voluntary bumping on the day of travel, and preventing customer-serve disasters arising from involuntary bumping of passengers.

Practically speaking, the system could benefit business travellers by freeing up seats occupied by leisure travellers for last-minute booking.

Flex-Scheduling is currently being tested with a small group of United Mileage Plus members.