Rock-bottom airfares are going the way of the zeppelin as fuel prices continue their climb into the stratosphere, the New York Times reports. Some budget carriers have gone bust. Others have hiked fares and begun to woo more business travelers, blurring the line between big carriers and discount operations. Southwest and JetBlue have ditched their caps on fares, airline china with JetBlue doubling its one-way cross-country fare to as much as $599.

“The reality is that fares must go up,” said a Southwest executive. "The arithmetic doesn’t work if we transport five people across the country at $99 each way.” Seeking to keep its thrifty image while raising fares, Southwest is now stressing its freedom from the extra fees that many big airlines have been tacking onto fares.