US airlines have warned of looming travel chaos as 5G mobile networks due to go live on Wednesday threaten to cause significant disruption across America. 

The chief executives of its biggest carriers have called for immediate action to halt the upgrade to prevent large numbers of planes being “indefinitely grounded”.

A letter signed by 10 airlines including United Airlines, American Airlines and Delta called on the transportation secretary, Pete Buttigeg, to create a two-mile exclusion zone around airport runways to prevent upheaval for passengers, freight, supply chains and vaccine distribution. 

United said 5G would cause disruption affecting 1.25m passengers and 15,000 flights a year if the mobile operators are allowed to turn on the 5G signals. 

Mobile giants Verizon and AT&T are poised to press the button after a series of delays due to fears the C-Band wireless spectrum could interfere with aircraft equipment.

They had vowed to carry out the upgrade regardless before bowing to pressure from US authorities to delay it until January 19. 

“Unless our major hubs are cleared to fly, the vast majority of the traveling and shipping public will essentially be grounded,” the airlines’ letter said. 

“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.”

Calls for a further halt comes after a one-month delay from the original December 5 launch date to avoid potential flight disruption. 

Last month, Airbus and Boeing also called on the Biden administration for a delay so they could better understand potential 5G interference with its radio altimeters, which measure the height of a plane.

The world’s largest passenger jet manufacturers share concerns held by aviation officials over C-band WiFi frequencies between 2.4GHz and 5GHz. 

Because the frequencies are close to those used by altimeters, there are fears it could make readings unreliable at a time when precise data is needed by pilots to land planes in bad weather. 

The Federal Aviation Administration has previously said such problems could lead to flight diversions. It added that other nations are using 5G bands that are unlikely to cause significant issues. 

The Civil Aviation Authority, its UK counterpart, said in November there was no evidence 5G would affect flights in Britain as operators do not use the same C-Band spectrum.