United Airlines is rolling out a new test program to deal with overbooked flights.

The airline will sell seats that are already booked to other flyers willing to pay a higher price and offer vouchers to passengers on oversold planes up to five days in advance to change their tickets.

The airline was heavily criticized in April after a passenger was dragged off an overbooked flight.

CBS News travel editor Peter Greenberg joined "CBS This Morning" from Tampa to discuss how the plan works and what it would mean for both the airline and the consumers.

It's called the "Flex-Schedule" program. Passengers sign up for a newsletter indicating that they would be available to take another flight that same day. If a flight fills up earlier than expected, those on the "Flex-Schedule" are alerted by email five days before the departure and offered the option to give up their seat for a different flight the same day. They also receive a flight voucher up to $250.

"The airlines get to manage their inventory of available seats better but most importantly they get to maximize their revenue for every available seat," Greenberg said. "It's about peak flights."

Asked if the person who opts for a "Flex-Schedule" seat is taking a risk, Greenberg said, "Well, they're not gonna take a risk because they don't have to accept the offer. But the point is, they will get that offer five days ahead of time which allows the airline to resell that seat at a much higher fare."

The aim of the five-day advance notice of a full flight is to help decrease the likelihood that a flight is overbooked when people are at the airport.

"The only people who are really gonna be unhappy about this are the passengers who like to game the system who are hoping that that flight is overbooked so they can get a higher payout at the gate," Greenberg said.

In a statement to CBS News, United Airlines said, "We are always looking at new ways to innovate and improve the customer experience and this extremely small test is an example of one of many opportunities we are reviewing."