DALLAS — The latest attempt by airlines to raise fares has collapsed.

United Airlines said Thursday that it rolled back an increase of $4 to $10 per round trip on many U.S. routes. Delta Air Lines, which had matched the price hike that United started on Tuesday night, dropped prices back earlier Thursday.

J.P. Morgan analyst Jamie Baker said the increase unraveled because it gained only limited support from a few other carriers — American, Alaska and US Airways. He said airlines have tried 12 fare hikes this year but only four have succeeded.

Airlines often abandon price increases when key competitors such as Southwest Airlines don’t match them, because consumers will change airlines for even a few dollars in savings.