Potentially, if there's no agreement on how it's all going to work. It's not where the company is based that's the issue, it's whether there's groundcrew and pilots with the correct paperwork (for the new way of things) to fly or work on them.So all those flights that travel to the UK will just stop? All those US airlines will not travel anymore and all those BA flights will just stop, remember BA is not a UK airline its HQ is in Madrid. All those contrails that I see above my house every day will turn left or right and land in France along with all the ones that are already landing there.
Of course, hopefully there'll be a deal before that happens.