There are plenty of different routings in to Madrid. Some people travel a day or two before, or a day or two after, some via Paris, Frankfurt; some fly into regional airports and get the train, some will get the ferry to Bilbao for that matter. It's never just a question of looking at point A to point B and adding up the number of aircraft needed to get there, but even if it was, there's plenty of aircraft available to do something like that. The reason charter flights to football are comparatively expensive is because there's little likelihood of them being re-used between the outbound and the inbound, so they become an expensive ornament sat on the tarmac waiting.