FARNBOROUGH, UK  -  Britain sought to project an image of aerospace prowess long after it leaves the European Union, at the Farnborough airshow on Monday, as Airbus and Boeing announced a raft of deals and issued optimistic outlooks for the global industry.

China's Sichuan Airlines said it will be buying 10 A350 long-haul planes with a list price of $2.8 billion, while India's Vistara signed a letter of intent to purchase 13 single-aisle A320neo aircraft.

Taiwan's Starlux Airlines, which is developing a network across Asia and North America, said it had signed a memorandum of understanding for the purchase of 17 Airbus planes - 12 A350-1000s and five A350-900s.

The Airbus deals announced at Farnborough, southwest of London, would add up to more than $17 billion at catalogue price for the planes if all orders are confirmed and prior to large discounts traditionally handed to purchasers.

Airbus's US rival Boeing also announced a series of impressive deals including 14 777s to DHL for $4.7 billion, 30 737 MAX for Jackson Square Aviation for $3.5 billion. "We continue to see the aerospace market grow very strongly," Boeing's chief executive Dennis Muilenberg said on the eve of the Farnborough show, echoing similar comments by Airbus.

No-deal warnings

But Farnborough is taking place in the shadow of a trade war between China and the United States as well as Britain's stalled negotiations to exit the European Union.

Airbus, which employs some 15,000 people in Britain, has warned it would reconsider investments in Britain if it crashes out of the European Union next year with no deal.

Airbus chief executive Tom Enders last month said the government had "no clue" over its Brexit plans.

After Prime Minister Theresa May unveiled more conciliatory proposals last week for Britain to retain strong trading ties with the EU after Brexit, Enders however said that the government was now "going in the right direction".

In a tweet he urged EU negotiators in Brussels and other European countries to be "similarly pragmatic & fair". Organisers also warned that aircraft could stop flying if May fails to clinch an adequate Brexit deal with Brussels.

"Our worst case scenario is genuinely - and it is not alarmist or scare mongering - that aircraft will not fly," said Farnborough International chairman Paul Everitt, who is also head of aerospace, defence and space trade body ADS.

May sought to play down concerns with an optimistic message in her inaugural speech at the show. "We're leaving the European Union and forging a new future for our country and, as we do so, want to ensure that the UK remains one of the best places in the world for aerospace companies to do business," she told participants. She said Britain wanted to "continue as world leaders in innovation" and announced £343 million ($456 million, 389 million euros) in public-private investment in innovative research and development, including new electric aircraft technology.

'Future fighter'

May also announced a new £2.0 billion programme with Italy's Leonardo to design a new generation fighter jet, following speculation that Brexit could disrupt cooperation in this field.

"Today I can announce that the government will join with BAE Systems, Leonardo, MBDA and Rolls Royce to fund the next phase of the Future Combat Air System Technology Initiative through a ground-breaking partnership known as Team Tempest," she said.

Defence Secretary Gavin Williamson said Britain had "a vision for developing next generation systems of weapons". He said the project would be carried out by a "ground-breaking partnership". "This is a future fighter... a virtual cockpit, either manned or unmanned," Williamson said.

Eurosceptics pressure May

British Prime Minister Theresa May drew fire from all sides Monday over her Brexit strategy as a former minister described it as a "fudge" and called for a second EU referendum while eurosceptics readied a parliamentary challenge.

Former education secretary Justine Greening, who opposed Brexit, said May's plan to follow European Union rules on trade in goods without being able to influence them was "the worst of both worlds".

Noting the deep divisions in government and parliament on the way forward, Greening said voters must decide - becoming the most senior member of May's Conservative party to back the idea. "The only solution is to take the final Brexit decision out of the hands of deadlocked politicians, away from the backroom deals, and give it back to the people," she wrote in an article in The Times. May has repeatedly ruled out a second referendum, after Britons voted by 52-48 percent for Brexit in 2016, but Greening's support for a so-called People's Vote will give the campaign a huge boost. Her intervention is also another blow for May's compromise plan for close ties with the EU, which had already come under fire from Conservatives who want a clean break with the bloc. Two top ministers, Boris Johnson and David Davis, quit in protest last week followed by a string of junior walkouts, including another on Monday.

Eurosceptics will have a chance to show their strength in the House of Commons later Monday by voting on amendments to a bill setting up May's new customs regime after Brexit.

Downing Street declined to say if it would accept some of the changes put forward by Jacob Rees-Mogg and other hardline Brexiteer MPs, in a bid to get them to drop one in particular that would have the effect of wrecking May's plan.

If no compromise is struck, there is a risk the eurosceptics could vote against the bill in its entirety. If opposition parties join them, May would have a major crisis on her hands.

At the same time, the prime minister is also testing her plan with the EU, as Brexit negotiations resumed in Brussels on Monday.