Ahead of the rollout of 5G services in the U.S., aviation regulators have cleared nearly half of the country's commercial airplane fleet to perform low-visibility landings.
The Federal Aviation Administration said on Sunday it had approved two radio altimeter models used in many Boeing and Airbus planes.
There have been fears the C-band wireless spectrum for 5G - due to be deployed by Verizon and AT&T from Wednesday - could interfere with the altimeters.
The altimeters measure altitude and help minimize the risk of accidents or collisions by giving an accurate reading of the proximity to the ground.
The FAA said Sunday's aircraft and altimeter approvals mean that runways at as many as 48 of the 88 airports most directly affected by 5G rollout will remain open.
But the agency went on to warn that flights at some airports may still be affected.
Last year, Verizon and AT&T won nearly all of the C-band spectrum in an $80 billion auction.
They have agreed to buffer zones around 50 airports to reduce the risk of interference.