Speculation is always fun. After all, everyone's theory has equal validity because no one knows what the outcome will be. What we all think matters and should be listened to.
Brexit has provided a lot of opportunity for speculation. Everyone in Europe expects it to happen. Everyone in Europe thinks it will have an effect. No one in Europe actually knows what the effect will be.
And that is the background to which Jean-Marc Janaillac began speaking to the topic recently. In an interview in the Guardian the Air France KLM CEO used a "back to basics" approach to explain how he saw the outcome.
Janaillac thinks that "no deal" will quite simply mean "no flying". No deal would mean that Britain's membership of the European Common Aviation Area would cease and with it the right for any carrier not owned predominantly by EU citizens to fly into and out of Europe.
The more likely outcome of a deal or, at least, a transitional arrangement would mean that British carriers would continue flying but Janaillac is clear on what basis. He believes that if Britain is to have the same rights as European carriers, it should also carry the same obligations. That means that it can continue flying but only if it continues to accept the jurisdiction of the European Court of Justice (ECJ). Brexit watchers know full well that the ECJ is a red line to many Brexiteers, a condition that they will not abide.
This takes us to some very interesting 'what if' scenarios. Brexiteers have been quite forthright and public in their contention that any acceptance of ECJ is unacceptable. To cling to such a policy, however, could result in UK aviation losing access to many European destinations, a fair chunk of their business by any calculation. Compromises are always possible but only if all parties are willing — would European carriers be willing for UK carriers to have different rules? Perhaps, but this would likely be agreed at a price.
At present IAG is trading near its historic high and is looking good for the future. Iberia, Vueling and Aer Lingus would clearly remain European carriers so the overall company volumes might not be affected if BA were to be excluded but as the shareholding is in IAG, it is not a done deal that BA would automatically be considered a British carrier.
Similarly easyJet has opened a European operation to allow its intra-Continental routes to continue.
The 'British' carrier which is most exposed is probably the one that is most clearly 'European', namely Ryanair. Brexit will not affect its Irish operations but the carrier has a massive presence in the UK and the survival of its many routes between the UK and airports in the remaining 27 could be challenging.
Courts may sound a technicality but the Brexiteers have been very clear and vocal in their view that there will be no future role for the ECJ in anything that is British.
It could yet be a rocky flight path for British carriers.