If I may be so bold as to inject some factual information into the discussion;
From The Financial Times, 27th November 2017, "UK Airlines risk losing flying rights, says Brexit paper"
If Britain left the single market, the paper states, UK-owned airlines would automatically lose existing flying rights in Europe’s “fully liberalised” aviation market, and would no longer be entitled to EU recognition of approvals for parts or certificates for airworthiness.
https://www.ft.com/content/e7674638-...1-794ce08b24dc
In a later piece from Euronews carrying a Reuters report from 12th December 2017
British airlines will lose all flying rights the European Union has negotiated with third countries as well as those negotiated by individual EU states after Britain quits the bloc, the EU executive said in a note. They would also lose flying rights under agreements between individual EU member states and third countries as they would not longer be considered EU airlines.
EU warns British airlines on post-Brexit flying | Euronews
And those at the coal face of the aviation industry agree.
BALPA's position even before either of the above from 10th October 2017
Commenting on suggestions by the Prime Minister that a Brexit ‘no deal’ was now an option, BALPA General Secretary Brian Strutton said:
“The entire UK aviation sector which employs nearly a million people and carries more than 250 million passengers per annum would be devastated by a Brexit ‘no deal’.
“Unlike most other sectors there are no World Trade Organisation or any other rules to fall back on for aviation if there is no deal.
“UK airlines could find they have to stop flying – it’s that serious. And this would impact passengers long before March 2019 because airlines couldn’t sell advance tickets and, frankly, would passengers risk buying them?
https://www.balpa.org/Media-Centre/P...spell-disaster
JAS