How far apart do planes fly from each other in europe ?

Answer 1

Recent regulations (RSVM) require aircraft to remain at least 1,000 feet of vertical seperation from each other. Air traffic control tries to avoid aircraft on the same horizontal course as well.

Answer 2

You're asking many questions about planes today. Are you worried about something?
At max. altitude, they can be around five miles from eachother but normally much more than that.
As planes descend into an airport, their distance becomes less. You can sometimes see a queue of planes landing, which are flying about two or three miles apart.