AT&T and Verizon are rejecting a request from the FAA to delay the rollout of their new 5G wireless services any further.
The cellphone carriers sent a letter Sunday saying they plan to start it up on Wednesday after they had already agreed to a costly delay.
U.S. Transportation Secretary Pete Buttigieg had expressed concern that the 5G launch could potentially disrupt the airline industry.
But AT&T and Verizon Communications argue the potential interference from 5G signals can be mitigated.
The wireless companies believe any further delays would be to detrimental to millions of customers.