The European Union may attempt to strip British airlines of some flying rights after Brexit, with officials in Brussels warning that U.K.-based carriers could see their ability to compete across the bloc impeded.

A meeting of the European Commission and diplomats from the remaining 27 EU countries has taken the first steps in sketching out the EU’s negotiating position on post-Brexit aviation links with Britain. If this becomes the EU’s stance going into the next phase of the talks, it would be another indication of the tough line being put forward by the bloc, following last week’s strengthening of the proposed language on the transition period.

The discussions on Tuesday came a day before technical talks between British and EU officials resumed on Wednesday for the first time since an interim divorce agreement was reached more than a month ago. The EU-U.K. session represents the beginning of what will be at least nine months of wrangling aimed at agreeing on a transition arrangement and the outlines of the future trading relationship between Britain and the EU.

Britain’s withdrawal from the bloc means that there would technically be no agreement to enable planes to fly between the U.K. and the EU. Unlike when it comes to the trade in goods, there is no fall-back option of World Trade Organization rules when it comes to aviation, the European Commission said in a presentation to the diplomats, according to information published on its website on Wednesday.

U.K.-based airlines currently benefit from all nine air “freedoms” accorded to members of the EU, the most generous of which allows the right to fly solely within a foreign country. It’s this freedom that allows, for example, EasyJet to operate between the French cities of Nice and Paris.

Court of Justice

In Tuesday’s meeting, the commission signaled that the U.K.’s refusal to sign up to European Court of Justice jurisdiction, and other obligations under EU law, risked it having the same relationship in aviation as the EU now has with the U.S. and Canada, a person familiar with the discussions said.

This would give U.K.-based airlines only the third and fourth and potentially fifth “freedoms,” which would permit flights between the U.K. and EU countries, but not the right to offer domestic flights within an EU nation or to fly between two EU states.

The aviation relationship would probably remain as it is now when the U.K. is in the yet-to-be agreed transition period between its departure from the bloc in March 2019 and 2021, although the U.K. would lose its seat in the European Aviation Safety Agency except in exceptional circumstances.

All 27 remaining member states still need to agree on a common negotiating position on aviation and then start discussions on the issue with the U.K., which is likely to push for a more liberal agreement.

In the meetings between the U.K. and EU on Wednesday, officials discussed issues left over from the negotiations that ended in December over the U.K.’s divorce from the bloc, including the difficulty posed in keeping a soft Irish border, as well as on the extent to which the European Court of Justice will be involved in enforcing the final agreement.