I'm looking at doing short weekend European trips using Avios, but for such a trip I don't want to have to encounter long/expensive transfers from the airport to the city. What airports are close to the city centre and easy/cheap to get to?

I'll start (to make this into a discussion):
CPH / Copenhagen: 10 minute metro, ~£3
KRK / Krakow: 15 minute taxi, ~£10 or Uber, ~£5
WAW / Warsaw: 15 minute taxi, ~£10 or Uber, ~£6

Sorry if something like this has been posted/discussed before.