WASHINGTON, Oct 10 (Reuters) - Delta Air Lines ( DAL )

and Aeromexico challenged a Trump administration decision

ordering them to unwind a joint venture by January 1 that let

the carriers coordinate scheduling, pricing and capacity

decisions for U.S.-Mexico flights.

The companies filed a legal challenge to the U.S.

Transportation Department decision last month in the 11th

Circuit Court of Appeals that was made public Friday. The

department ordered an end to the nearly nine-year-old joint

venture as part of a number of actions aimed at Mexican

aviation, citing competition concerns.