Yeesh, OP asked a pretty simple and broad (which makes it even easier to offer answers) question and half a dozen posters want to jump down his throat. I find the topic fascinating even though I can't really offer any expertise on this front, so it's great to see the helpful responses.
Originally Posted by
Sheikh Yerbooty
Those who are not geographically challenged will have noticed these suggestions are at the opposite corners of Europe, and serves only to illustrate the daftness of the OPs question.
Daftness? It's a worthwhile question and stopping over between Asia and the US I'm quite sure the OP wanted to leave all corners of Europe on the table. He specified locations close to major airports, I would imagine that is the main parameter.