The whole precess of the UK leaving the EU could be made a lot smoother but the resentment, anger and frustration from the EU side, is still very much palpable. Unless this subsidies, then progress shall be slow and painstaking. Hearing the very recent quotes of Tusk saying he is 'furious' about Brexit and Verhofstadt using such an adjective on BBC as 'stupid' to describe the process, shows the strong level of bitterness that still exists. This will do little to appease the politicians who are staunch supporters of Brexit and especially with the overflow of raw emotion and feeling from the EU side.
I get the feeling that those with any degree of influence and control within the EU, seem to be determined on going out of their way to make the Brexit process as complicated and as painful for the UK, as it possibly can be. The ramifications for the aviation industry could be significant but it doesn't have to be this way. It could be far more harmonious!!!