The transport secretary has acknowledged that flights between the UK and the European Union could be grounded from 1 January 2021 in the event of a no-deal Brexit.
At present, UK and EU airlines are able to fly any routes they wish under the long-standing “open-skies” agreement within Europe.
That comes to an end on 31 December, as the Brexit transition period ends.
Grant Shapps told the virtual convention of Abta, the travel association: “We’re seeking arrangements that will maintain connectivity.”
But his remarks made it clear that, with 78 days to go, there is currently no legal framework for flights to continue to operate from 1 January 2021.
Mr Shapps said: “For road and aviation, both sides are in broad agreement that operators from the UK and the EU should have rights to provide services between the UK and EU and that will be the basis of agreement.
“We hope it will be possible to agree some sensible additional flexibilities. Despite public statements from Brussels we are not seeking to replicate our current single-market rights
“We are rather exploring some limited additional flexibilities for both road and air that would be of benefit to both sides. We hope the EU will engage with these.
“Negotiations as you know have been intensified in recent weeks, and although time’s now tight, we remain hopeful that an agreement can be achieved.
“It’s critical that flights between the UK and the EU can continue to operate as normal at the end of the transition period, regardless of the outcome of these negotiations.
“We expect the EU to bring forward contingency measures, as they’ve done before, to ensure flights will continue if negotiations are unsuccessful.
“Of course we would look to reciprocate that.”
Mark Tanzer, chief executive of Abta, said he was “concerned” by Grant Shapps’s admission.
“A year ago when we were coming up to potentially no deal, we had a ‘standstill' agreement that for a year, whatever the outcome, aviation rights to be able to fly back and forth to Europe would be in place,” he said.
“What the [transport secretary] was suggesting was that we are now waiting for a proposal from Europe that that will be the case."
Mr Tanzer said that with barely 11 weeks remaining before the transition period ends, traveller confidence would be eroded still further.
"People are wanting to book way beyond that, and if they are not sure that the flights will fly, that will be just another deterrent for making people pause before they book.
“An early statement from him and from the EU that, irrespective of what happens with the trade agreement, we’ll be able to the access Europe is absolutely essential.
“When we were looking at Heathrow expansion and Brexit, all the talk was about aviation connectivity is a strategic asset for the UK, a strategic necessity in a global world. Where is the evidence of that now?”
A spokesperson for IAG, which includes British Airways, Aer Lingus and Iberia of Spain, said: “IAG expects the EU and UK to agree a Comprehensive Air Transport Agreement. Flights will continue to operate as normal.”
Mr Shapps added that Eurostar trains between the UK, France, Belgium and the Netherlands would be unaffected.
“We do not need an agreement with the EU on rail as we can assure connectivity using other arrangements.”