>> reporter: the 5g signals could cause interruptions to airplanes' altimeters which are crucial for pilots during landing. at&t and verizon, which spent billions of dollars for these frequency, and the faa have yet to figure out how this will all begin. with just two days until at&t and verizon go live with their 5g coverage, the faa is getting very little cooperation from the major phone carriers. and overnight, the world's largest pilots union backed a top airline trade group calling to delay the rollout of 5g near certain airports. it comes after at&t and verizon declined a request from federal transportation officials to postpone the launch of their 5g signals for up to two weeks. the faa has warned this next generation of cell service could