Boeing and Airbus executives have urged the U.S. government to delay a 5G internet rollout, saying it could disrupt flight and radio equipment.

Boeing Chief Executive Dave Calhoun and Airbus Americas CEO Jeffrey Knittel wrote a joint letter on Monday to Transportation Secretary Pete Buttigieg.

They said, "5G interference could adversely affect the ability of aircraft to safely operate.”

Buttigieg’s office did not immediately comment.

The airline industry and Federal Aviation Administration (FAA) have raised concerns about AT&T and Verizon’s plan to deploy C-band spectrum 5G wireless early next year.

The FAA warned this month that 5G could interfere with sensitive aircraft electronics like radio altimeters and lead to flight diversions.

The rollout has already been delayed once in order to apply precautionary measures to limit interference, but aviation groups said those measures are insufficient.

Boeing and Airbus offered a counterproposal that would limit cellular transmissions around airports and other critical areas.

Meanwhile, wireless industry group CTIA said 5G is safe and accused the aviation industry of distorting facts and fearmongering.