Everyone has a price they would be willing to give up their seat and it will be different than the person next to them. If you are traveling on a last minute t

Everyone has a price they would be willing to give up their seat and it will be different than the person next to them. If you are traveling on a last minute ticket to visit a family member in the hospital, you might not be willing to delay your travel for any amount of money. If you are traveling on a vacation, the amount might be relatively little. Also some passengers will value some things more than others - offering a year of gold membership might entice a business traveller, offering money might entice a college student, upgrades to first class might entice others, etc. The idea that 100 people have the same utility curves is not reasonable. Obviously it is more efficient for everyone if this bidding is done before you get to the airport, the system described in the article is one example.