Ryanair, the largest European airline by passenger numbers, confirmed that it applied for a United Kingdom air operator’s certificate in December 2017. The move is seen as the preparation for the ‘worst case scenario’, as it would allow the Irish low-cost carrier to continue flying within the UK in case no favorable aviation agreement is during Brexit negotiations.

First mentioning the possibility in 2016, Ryanair has finally applied to the UK Civil Aviation Authority for an air operator’s certificate through its subsidiary Ryanair UK, according to the statement given to Sky News, which first reported the news. The move "may be required for Ryanair's three UK domestic routes in the event of a hard Brexit in March 2019".

It was easyJet that first made a similar move back in July 2017. The second-largest European low-cost carrier, which is based in the UK, obtained an Austrian air operator's certificate, protecting itself from the possible legal consequences of Brexit - Britain's seemingly inevitable withdrawal from the EU. The newly established airline is called easyJet Europe. For the time being, it will operate only one aircraft, which made its first flight on July 20, 2017.

The precautionary measure is not the first Ryanair’s response to uncertainty regarding airline arrangements post-Brexit. In July 2017, the airline announced it might cancel flights and move at least some of the UK-based aircraft to continental Europe if there is no clarity on whether the UK remains covered by the EU Open Skies.

Although the negotiations over the access to European markets after Britain leaves the EU are just starting, several airlines operating in the UK have already expressed deep concern and plan to move some – or all – business to continental Europe. easyJet has already obtained an Austrian air operator's certificate (AOC), and Ryanair has been quoted to look into the possibility of moving shop. So, what does the post-Brexit world hold for airlines?  

In August 2017, however, the carrier joined Airlines UK, the industry body representing UK-registered airlines as an “international airline member”, a new tier of membership that allows non-UK carriers. “Ryanair is the largest airline in Europe with a substantial presence in the UK,” said Tim Alderslade, Airlines UK Chief Executive in a statement at the time. “[…]Their membership will further strengthen our ability to advocate on behalf of a sector that is such a vital UK and European success story and we look forward to working with them.”

Residents of Britain voted to leave the EU in a referendum on June 23, 2016. The country is expected to officially part ways with the EU in March 2019.