HOUSTON, Dec. 28 (Xinhua) -- Several U.S. airlines said Tuesday that they are raising airfares on domestic routes as air travel is boosted by the Christmas-New Year holiday season and the industry is facing rising fuel prices.

United, Continental and Delta confirmed Tuesday that they are raising fares. Prices on many domestic routes are up by 10 dollars one way and 20 dollars per round trip.

Some 2.75 million Americans will travel by air to holiday destinations during the 11-day period that began Dec. 23, a 2.8 percent increase from a year ago, an industry report said.

Meanwhile, airlines also face rising jet fuel prices. Crude settled above 91 dollars a barrel in the final week of trading before the new year, underscoring the pressure on an industry whose two largest costs are jet fuel and labor.