Systems and methods for boarding passengers on flights or other transportation according to bids received from the passengers are provided. Passengers seeking to fly standby on an undersold flight can submit a bid representing the amount the passengers are willing to pay to board the flight. The airline can determine the number of seats available on the flight, and board the highest bidding passengers until the flight is full. Similarly, passengers willing to be bumped from an oversold flight can submit a bid representing the incentive the passengers are willing to accept to be bumped from the flight. The airline can determine the number of passengers that must be bumped from the flight, and bump the lowest bidding passengers (i.e., those willing to accept the least costly incentive) until a sufficient number of passengers have been bumped from the flight.