MIAMI – Two major carriers, Verizon and AT&T, are delaying the launch of 5G near U.S. airports, including Miami International Airport and Fort Lauderdale-Hollywood International Airport.

CEOs from American, United, Delta and seven other major carriers warned of “significant” disruptions in the country’s aviation system if the 5G rollout continued as planned.

Aviation officials are concerned that the frequency used for 5G may interfere with airplanes’ radio altimeters, devices used by pilots to measure the distance between the aircraft and the ground in order to land.

In the letter, U.S. airline leaders wrote to government officials Monday asking that the wireless carriers not deploy 5G within two miles of runways at certain airports.

President Biden said his “team has been engaging non-stop with the wireless carriers, airlines, and aviation equipment manufacturers to chart a path forward for 5G deployment and aviation to safely co-exist.”