Southwest Airlines is making a 180-degree turn and raising fares on many routes by up to $10 per round trip.
The self-proclaimed low-fare airline declined to match a $10 increase by United Airlines earlier this week, helping force United to roll back prices.
But on Friday, Southwest raised fares $2 each way for trips under 501 miles, $3 each way for 501 to 1,000 miles, and $5 each way for longer trips.
Brad Hawkins, a spokesman for Dallas-based Southwest Airlines Co., says the reason is simple: The airline's costs are rising.
J.P. Morgan analyst Jamie Baker says Southwest started by raising prices on a limited number of flights, then broadened the increase and included flights by its AirTran Airways subsidiary. He expects most other airlines will match it by Saturday.