British travellers heading to the US have been warned they could be caught up in travel chaos on Wednesday as two of the country's biggest mobile providers switch to 5G.
Bosses of the top American airlines have written to the White House about their concerns, and fear planes could be grounded and routes cancelled due to the roll out.
Mobile internet providers Verizon and AT&T are switching to 5G but the airlines are concerned they will use a similar wavelength to vital instruments used on their planes and they could interfere with each other.
There was no such concern when 5G was rolled out in the UK.
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In the letter, which had the subject line: immediate action to address 5G interference with national aviation system, the airlines ask for the 5G network not to be implemented within two miles of airport runways.
It states: "Unless our major hubs are cleared to fly, the vast majority of the travelling and shipping public will essentially be grounded.
"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 letter was signed by CEOs of American Airlines, Delta, Jetblue, Alaska, FedEx Express, Atlas, United, Southwest, Hawaiian, UPS and Airlines for America.
Travel expert Paul Charles told the Daily Mail: "There's no evidence of any problems in other countries including the UK of 5G interfering with aircraft safety systems, so I think it's a case of American airlines needing more education before 5G can be rolled out.
"But from a passenger point of view, the advice is to plan your trip as normal and check for any cancellations."
A spokeswoman for the Civil Aviation Authority in the UK said: "We are aware of reports that suggest the frequency band being used for 5G in a number of countries could potentially pose a risk of interference with aircraft radio altimeters.
"There have been no reported incidents of aircraft systems being affected by 5G transmissions in UK airspace, but we are nonetheless working with Ofcom and the Ministry of Defence to make sure that the deployment of 5G in the UK does not cause any technical problems for aircraft."
Gareth Elliott, Head of Policy and Communications at Mobile UK, added the networks were working with the aviation authorities to "ensure there was no interference in the UK".
