British aircraft “would not be allowed to fly” in the event of a no-deal Brexit unless new arrangements for commercial flights are introduced by March, a think tank has said.

There is no fall-back plan for air traffic control rights under World Trade Organisation rules in the event a deal cannot be struck with Brussels, the Institute for Economic Affairs warned.

But the IEA stressed there are options available to the Government to put measures in place before March - and while it would “require flexibility on both sides”, there is an “overwhelming” mutual interest in protecting aviation from upheaval.

In the first of a series of “no deal fear checker” reports released on Monday, it said the risk of flights being grounded was “conceivable, but still very unlikely”.

The report said leaving the EU’s Single Aviation Market (Sam) in March without a replacement arrangement would see most UK-based airlines lose their operating licences for the 27 countries.

Sam currently covers the UK’s rights to the so-called “freedoms of the air”, which include overflights of countries without landing and operating internal flights in foreign countries.

The UK would also lose air traffic rights to countries including the United States, Canada and Switzerland because they had been made through the EU.

In the report Julian Jessop, the IEA’s chief economist, wrote: “In summary, if there are no alternative arrangements in place, it would be as bad as the worst fears suggest: planes would not be allowed to fly.”

However, the report said there were options open to the Government.

It could “immediately” join other non-EU countries Norway and Iceland as members of the European Common Aviation Area (ECAA), although this “off the shelf” option would mean following existing EU rules and “fudging” some of the Government’s Brexit “red lines”.

Or negotiate a bespoke free trade agreement for aviation which would give the UK more control over the rules but could also mean “reduced access to the EU market” and “would also take longer to agree”. Negotiations would be made more difficult if the EU takes a hard line in the event of a fractious no-deal Brexit, it adds.

There are also three “reasons for optimism” that the worst-case scenario would not be realised, it found.

The UK is a world leader in aviation, which means it has “plenty of leverage” as the largest market in Europe and the third largest in the world.

The report also says there are strong mutual interests in a beneficial arrangement: “Grounding UK airlines would be hugely damaging for the EU economy, particularly in areas like tourism.

“And, of course, foreign airlines presumably want to continue to fly to and from the UK as well.

“Since these agreements are reciprocal, it is unlikely that other countries would deny the UK the most important rights when they would then almost certainly lose them too.”

It continues: “Third, even if this is left to the last moment, there are several quick fixes.

“In particular, the UK and EU [or a third country like the US] could agree at least a temporary extension of the current arrangements by something as simple as a memorandum of understanding.

“The key question for the EU is whether the necessity of keeping planes flying outweighs any threats to the integrity of the single market or the risks of giving the UK special treatment - the answer must surely be ‘yes’.”