According to the U.S. Federal Aviation Administration, 45% of U.S. commercial aircraft fleet was cleared Sunday for low-visibility landings at airports in which 5G C band will be used starting Wednesday.

FAA warned of potential interference that could impact sensitive aircraft instruments like altimeters or low-visibility operation.

Senior government officials have heard from U.S. cargo and passenger airlines that this issue has not been resolved yet and may severely affect flights and supply chains.

Airlines for America is a trade association representing American Airlines and Delta Air Lines.

Two radio altimeter designs were approved by FAA and used in many Boeing and Airbus airplanes. These include the Boeing 737 and 747 planes.

A319, A320 and A321, as well as A330, A330, and A350 models. The announcement came just days before AT&T and Verizon launch new 5G service on Wednesday. According to the FAA, it anticipates issuing more approvals over the next few days.

FAA stated that the new aircraft and altimeter approvals allow for “runways to as many as 48 airports which are most affected by 5G-C-band interference.” The FAA cautioned that even though these approvals have been granted, certain airports might still be affected.

Reuters has reviewed the 36-page listing of runways included in the approvals. It is not public and does not contain many large U.S. airfields.

Boeing was informed by the FAA in a Sunday review of Reuters that they were granting permissions to runways and planes with specific altitudes “because interference from 5G-C-band emissions has been reduced.”

AT&T and Verizon, which won nearly all of the C-Band spectrum in an $80 billion auction last year, on Jan. 3 agreed to buffer zones around 50 airports to reduce interference risks and take other steps to reduce potential interference for six months. The two sides also agreed that they would delay deployment by two weeks to avoid any aviation safety issues.

On Thursday, the FAA issued almost 1,500 notices outlining the potential impacts of 5G services.

According to the FAA, passengers are advised to check with their airlines whether there’s a possibility of 5G interference at their destination.

January 7th, the FAA revealed the 50 U.S. airfields to have 5G buffer zone. These zones include New York City, Los Angeles (Chicago), Los Angeles, Chicago and Las Vegas.

However, airlines caution that these buffer zones might not be sufficient to stop flight disruptions at airports.

On Thursday, Airports Council International – North America urged a delay 5G implementation to avoid widespread disruption across the U.S air transportation system.

FAA stated Friday that Boeing 787 flight crews would need to use extra precautions in landing on snowy or wet runways.