RIYADH (Reuters) -Delta Air Lines ( DAL ) is seeing a "small" impact from the U.S. government shutdown, costing it less than $1 million a day, and the shortage of airport security staff is of greater concern, the carrier's CEO said on Monday.

"The more obvious concern is TSA (Transportation Security Administration) and ensuring that those checkpoints are staffed accordingly," Delta CEO Ed Bastian told Reuters on the sidelines of the Fortune Global Forum in Riyadh.

There is also a shortage of air traffic controllers in the United States. Some 13,000 air traffic controllers and about 50,000 Transportation Security Administration officers must work without pay during the government shutdown. Controllers will miss their first full paycheck on Tuesday.

"Air traffic control is something in the U.S. that is understaffed to begin with. So it's hard to sometimes identify what is attributable to the shutdown versus just understaffing in general," Bastian said.

Delta is locked in a dispute with the U.S. government over its nearly nine-year-old joint venture with Aeromexico, which the U.S. Department of Transportation has ordered must end on January 1, as part of several actions aimed at Mexican aviation, citing competition concerns.

"We believe that the dissolution of our joint venture, particularly because of (Antitrust Immunity) is not the right strategy and something that we have to ensure that we protect our interests here for the long term," Bastian said, adding that he sees no timeline for a resolution of the issue. 

"We've been in conversation (with the administration) for a long time," he said. 

The joint venture allows the two carriers to coordinate scheduling, pricing and capacity for U.S.-Mexico flights.