The EU is more than a simple trading bloc. The single market and a web of complex standards, regulations and mutual recognition treaties means that (to a large extent) goods and services produced in one EU country can be treated exactly as if they were made or carried out in any other EU nation. One example of this is the aviation industry where national pilot qualifications are mutually recognised across the bloc and aviation components made in one country are accepted in all 27 other member states. Open Skies means that any domestic EU airline has the right to fly into any other nation’s airports with advantages to all EU citizens.
If the UK crashes out the EU on 29/3/19 without a transitional deal in place, these common standards between the UK and its EU partners will lapse overnight. Understanably, the EU is resisting calls from the aviation industry for parallel talks on the future of EU-UK aviation (as it is a state level matter). The sector is worth £193 billion to the EU as a whole.
In the event of state level negotiations breaking down, the General Avaiation Managers’ Association notes: “Our risk analysis concludes that EASA and the CAA need to urgently begin technical and contingency planning discussions by the June European council, and separate to the political negotiations. Without an agreed solution ... supply chain disruption across Europe will occur, parts will be unable to be delivered, pilots and maintenance technicians will be unable to work, aerospace companies in the UK will lose foreign validations for their business, and aircraft will be grounded globally.”
The UK hopes to remain as part of EU agencies which are key to aviation agreements, but the Commission seems unwilling to negotiate a deal with the UK as a third country which replicates the current situation it enjoys as an EU state. Currently, there are 35 common pieces of shared legislation, a common regulator, the EASA, and the ECJ which adjudicates in the event of a dispute. Theresa May remains insistent that the ECJ should have no role to play in the UK after Brexit. Outside of the EU, UK based airlines would need to have an EU headquarters and be 50% owned and controlled by EU nationals to fly within the EU (but not between the EU and the UK, of course, which would be a third-party nation by then); for example an Easy Jet flight between Vienna and Paris.