When the flight boards, agents give any available seats to standby passengers, who wait at the gate to be called.
Standby passengers typically have priority based on how much they paid for their tickets and their relative status in the airline's frequent flyer program.
[citation needed] Some low-cost carriers, Southwest Airlines in particular, have policies that only allow full fares to standby (unless the passenger's original flight was delayed).
[citation needed] Standby for earlier flights began as a free service on many airlines, but as of April 2010, most US airlines charge for unconfirmed standby, with a USD $50 to $75 fee being common.
American Airlines restricts free standby to passengers with elite status or fully refundable tickets, and charges $75 to all other passengers who want a confirmed standby seat within 24 hours of their desired flight time.