DALLAS — Several U.S. airlines have raised fares by up to $10 per round trip.

Rick Seaney, CEO of FareCompare.com, said Wednesday that American Airlines started the increases by boosting prices on flights over 500 miles by $5 each way or $10 roundtrip, and by $3 each way and $6 roundtrip for shorter trips.

American Airlines spokesman Tim Smith confirmed the fare increases. He said fares are dictated by supply and demand, and were also influenced by recent increases in fuel costs.

The higher fares were matched by United, Continental, Delta, Southwest, US Airways, Alaska, Frontier and Virgin America, making the increase likely to stick, Seaney said.

Competition on price is so intense in the airline business that carriers often abandon fare hikes if rivals refuse to match them. Several other fare increases failed in 2010, so U.S. airlines have turned to other means of boosting revenue, including imposing surcharges on peak travel days and selling fewer seats at the lowest advertised prices.

Airlines are relying on a range of other fees to raise revenue. This week, the U.S. Transportation Department said that through the first nine months of 2010, domestic airlines had raised more than $4.3 billion from fees for checking bags or changing flight reservations.

Seaney said that with rising prices for oil and jet fuel, airlines are likely to try to raise prices again heading into 2011.