Delta Air Lines raised many of its high-end, last-minute tickets by $4 to $10 per round trip, these include most of tickets sold with seven days of the trip, including first-class, instant-upgrade and unrestricted economy-class seats that are usually preferred by corporate travelers. Tickets that must be bought 14 or 21 days in advance were not affected; those seats usually cost less and appeal mostly to leisure travelers.

United failed at an attempt to increase economy prices two weeks ago after others rivals did not match. Other carriers said they had not matched it but didn’t rule out a fare hike.