As telecommunication giants Verizon and AT&T prepare to roll out their hotly anticipated new 5G service on Wednesday, major U.S. airlines are warning that the launch will result in “catastrophic” disruption for the aviation industry.

What are they saying?

In a letter sent Monday to Biden administration officials, a group of airline CEOs stressed that the forthcoming C-Band 5G deployment would ground “huge swaths” of the U.S. fleet and “could potentially strand tens of thousands of Americans overseas.”

“Unless our major hubs are cleared to fly, the vast majority of the traveling and shipping public will essentially be grounded,” they said in the letter, viewed by NBC News.

The airline executives stated plainly that the rollout could be accompanied by an aviation crisis the likes of which the country has never seen.

“To be blunt, the nation’s commerce will grind to a halt,” they stated plainly.

The letter was reportedly signed by the CEOs of American Airlines, United Airlines, Delta Air Lines, Southwest Airlines, and Jet Blue, as well as by leaders of shipping companies UPS and FedEx.

What else?

Fifth-generation wireless technology, known simply as 5G, is expected to deliver ultra-fast internet speeds, massive capacity, and increased connectivity to users. However, the chief executives argued that, as it stands, 5G signals would interfere with safety equipment that pilots rely on to take off and land in inclement weather.

CNBC noted that the Federal Aviation Administration has indeed warned that potential interference could affect sensitive airplane instruments such as altimeters, which measure the distance from the bottom of an aircraft to the ground during low visibility operations.

As of Sunday, the FAA had only cleared an estimated 45% of the U.S. commercial airplane fleet to perform low-visibility landings at airports where the 5G service would be deployed.

“This means that on a day like yesterday, more than 1,100 flights and 100,000 passengers would be subjected to cancellations, diversions, or delays,” the CEOs cautioned in the letter, adding, “Immediate intervention is needed to avoid significant operational disruption to air passengers, shippers, supply chain and delivery of needed medical supplies.”

The letter was sent to Transportation Secretary Pete Buttigieg, National Economic Council Director Brian Deese, Federal Aviation Administration Administrator Stephen Dickson, and Federal Communications Commission Chairwoman Jessica Rosenworcel.

Anything else?

As a way to avoid catastrophe, the airline CEOs urged that the rollout be delayed once again to give more time for the aviation industry to make necessary adjustments. Earlier this month, Verizon and AT&T agreed to delay the launch from Jan. 5 until Jan. 19 at Buttigieg’s request.

Airline leaders also suggested the service be rolled out “everywhere in the country except within the approximate 2 miles of airport runways at affected airports.”

“This will allow 5G to be deployed while avoiding harmful impacts on the aviation industry, traveling public, supply chain, vaccine distribution, our workforce, and broader economy,” they said.