Flights between UK and EU after a no-deal brexit

The president of the European Commission gave a speech today where he said:

The measures we and the Member States have taken will mitigate the worst impact of a “no-deal” scenario. The protection offered is real. The measures will make sure that EU and UK citizens can continue to live and work where they are at the moment. They make sure that planes can take off and land.

Question: Which concrete pieces of EU legislation (or other official documents) does the bolded sentence refer to?

I assume it must refer to a unilateral decision by the EU27 to allow British-registered aircraft to keep flying to/from EU airports. What I dare not make assumptions about is e.g. whether it is conditional on reciprocity. The UK politicians don't look like they have their act sufficiently together to have enacted reciprocal rules yet.

[Yes, this is a real question. I'm trying to decide whether to risk scheduling a business trip to England at the end of April, or keep waiting for more clarity. If there's a unilateral pledge by the EU27 that would not be canceled by lack of immediate reciprocity, booking BA tickets might feel reasonably safe. I believe the question to be reasonably answerable, since it concerns rules that, unless Juncker is a complete liar, must already exist -- not guesswork about the future].