Delta Air Lines Inc. and American Airlines have matched United's increase in the fee for changing a domestic-flight reservation to $200 from $150.
With US Airways Group Inc. having matched the increase last week, all four of the so-called legacy airlines have raised the cost of changing a ticket.
United Continental Holdings Inc. has said that it incurs costs when a customer changes a reservation and the higher fee compensates for the cost.
Delta spokesman Anthony Black said Thursday that his airline "closely monitors competitive conditions and periodically reviews its pricing of fees. After careful consideration, Delta increased its change fees to remain competitive in the marketplace."
Matt Miller, a spokesman for AMR Corp.'s American Airlines, noted that American sells fares called "Choice Essential" and "Choice Plus" that allow customers to change reservations at no extra cost. The tickets cost more than a base economy fare, however.
Southwest Airlines Co. does not charge a change fee, but it recently announced a new policy on no-shows. Passengers on the cheapest tickets will have to cancel a reservation before departure, otherwise they won't be able to apply credit from the missed flight toward a later trip.
Major U.S. airlines have increased revenue from extra fees in recent years, saying that customers should pay extra for extra services.