Airlines in the United States are asking the Federal Communications Commission to delay next week’s scheduled rollout of new 5G wireless service near dozens of major airports, saying it could interfere with electronics that pilots rely on.

Airlines for America, a trade group for large U.S. passenger and cargo carriers, said in an emergency filing that the FCC has failed to adequately consider the harm that 5G service could do to the industry.

The group wants more time for the FCC and the Federal Aviation Administration, which regulates airlines, to resolve issues around aviation safety related to a type of 5G service called C-Band.

“Aircraft will not be able to rely on radio altimeters for numerous flight procedures and thus will not be able to land at certain airports,”‘ the group said in a filing Thursday. Radio altimeters measure the height of planes above the ground.

A4A, as the group is called, said its 11 member airlines face the need to reroute or cancel “thousands” of flights, resulting in losses topping $1 billion.

The group said the new service will affect all three major airports in the New York City area—LaGuardia, Kennedy and Newark, New Jersey—as well as O’Hare in Chicago, Logan in Boston, Dallas-Fort Worth, Los Angeles International and San Francisco.

The trade group’s general counsel threatened to go to court next week if the FAA does not respond to the group’s request for a delay.

The FAA said in early December that it will restrict pilots from using automated landing systems at certain airports after the rollout of 5G or fifth-generation wireless service because it could interfere with radio altimeters. The FAA declined to comment on the airline group’s filing.

CTIA, a trade group representing the wireless-communications industry, did not immediately respond to a request for comment.

Rep. Peter DeFazio, D-Ore., chairman of the House Transportation Committee, sided with the airlines, saying Friday that the aviation and telecom industries should work together “to find a safe way to deploy 5G technologies…. We can’t afford to experiment with aviation safety.”

AT&T and Verizon Communications previously agreed to a one-month delay in 5G, which provides faster speeds when mobile devices connect to their networks and allows users to connect many devices to the internet without slowing it down.