Its almost like a college essay question so apologies in advance.
End of freedom of movement in March 2019: discuss the post brexit impact on low cost airlines like Easyjet and Ryan Air.
My one word answer would be: Devastating.
It would be if no agreement is put in place that ties in with the EU Open Skies Agreement although with easyJet having an Austrian AOC and Ryanair an Irish one that should solve part of the problem for these airlines, at least on intra-EU routes.
Many EU countries are hugely reliant on UK passengers for such things as tourism and it's unlikely that their governments would be prepared to cut off their nose to spite their face.
The same thing applies to talk of needing a visa when UK citizens visit European countries. It didn't happen before the UK joined the EU, at least not for Western European countries, and many of the former Eastern Bloc countries are now 'westernised'.
The snag with Brexit is the same snag that obtained in the run-up to the referendum. No-one knew what the result of a Leave vote would mean. We had all sorts of scenarios from both sides of the argument but no-one could know. They ranged from wild speculation to serious 'guestimates'.
Today another study has suggested that Bristol's economic output will suffer more than most cities post Brexit, especially if it's a hard Brexit, principally because the city is home to such a high number of law and accountancy businesses and firms that will be hit hardest by increased trade costs following the departure from the EU (joint Centre for Cities and Centre for Economic Performance study).
Against that a spokesman for the authors of the study said, “However, the good news is that Bristol is also better-placed than most other cities to respond to the downturn ahead, thanks to the city’s large share of high-skilled workers, innovative firms and strong business networks. All of these factors will be crucial in helping Bristol to adapt and reinvent its economy, and to continue to thrive as the UK’s economic circumstances change.”
Bristol has been continually reinventing itself as an economic centre, from the inter-war Depression Years right through post-war austerity and the various recessions since. It's always managed to do so successfully - in spite of inept local government leadership going back many decades and involving all political parties - and to be less affected than most cities, as it was in the Depression and in the major recession of the 'noughties' in this century.
So yet another example of what might or might not happen in a post EU era, albeit this is the work of a reputable and serious group that, as far as I know, has no interest in promoting either side of the argument for its own sake, unlike many organisations; and it still comes up with a suggested remedy.