FILE PHOTO: An American Airlines Boeing 767-300 aircraft takes off from Zurich Airport January 9, 2018. REUTERS/Arnd Wiegmann

(Reuters) - American Airlines AAL.O said on Thursday it would begin basic economy pricing on some long-haul flights, turning up the heat in a fare war over traditionally lucrative trans-Atlantic routes.

Starting in April, the largest U.S. airline by passenger traffic will offer no-frills tickets on select trans-Atlantic flights as it seeks to fight off large rivals and emerging competition from low-cost carriers.

American, Delta Air Lines DAL.N and United Airlines UAL.N have each introduced cheaper fares on a variety of routes lately to match fares from fast-growing budget competitors such as U.S.-based Spirit Airlines SAVE.O and Scandinavia's Norwegian Air, which have ramped up their schedules in the last several months.

Basic economy tickets typically include fewer complimentary offerings and instead offer pricey add-on fees for seat selection, checked bags and other services.

“There is a large segment of the flying population who cares almost entirely about price, and we need to compete,” said American Airlines Chief Executive Doug Parker at an aviation conference in Washington on Thursday. “We need to give those customers a choice on American.”

The rollout will include fares with joint business partners British Airways, Iberia and Finnair.