trump and biden administrations, and competing agendas. but concern, the new fifth generation of cell service, 5g, operates on a radio spectrum that could bleed over and interfere with the plane's altimeter. the altimeters bounce a signal off the ground to give pilots precise distance off the ground. >> 50, 40, 30. >> reporter: critical for landing in poor visibility. the faa told pilots they would not be able to use altimeters at more than 80 airports near 5g sites, including large airport hubs in houston, dallas, la, new york, chicago, and seattle. the airlines warned that would lead to massive delays, diversions, and cancellations. >> faa has to go airport by airport, runway by runway, to do an analysis and clear the runways at airports so we can safely fly. >> reporter: the cell phone industry, which delayed the rollout twice and says 5g is safe. at&t took aim at the faa, saying, we are frustrated by the