UK Transport Secretary Grant Shapps signed a new bilateral air services agreement to secure the deal, the Department for Transport (DfT) has announced.
Secretary of state Mike Pompeo signed on behalf of the US.
Flights between the UK and the US currently operate under an agreement between the European Union and the US, but the Brexit transition period ends on December 31.
The DfT said the UK’s trading relationship with the US is worth more than £230 billion a year.
Mr Shapps said: “The air services agreement will allow us to continue to travel and trade with one of our closest friends and allies, working together to mutually boost our economies on either side of the Atlantic.
“This is just one of many steps we’re taking as we move towards a bright new future.”
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