I remember coming back from a Man Utd game a few years ago (I can't remember the actual city). There were 5 or 6 chartered flights heading back to Manchester after the game. Plus a few to other cities in the UK.

Most of the planes had landed in the morning, allowing the good citizens of Mancunia a full day "on the ale".

On arriving back at the airport, we found the bar was open (normally they are closed after a game). So, there were a couple of thousand people all over the airport when the flights started boarding.

It was like herding cats trying to get everyone on the correct flights.

Eventually, the ground staff gave up, and it was a case of "take any plane". I managed to get on the correct flight, but at least one of my party ended up on a different plane. He still made it back to Manchester though. I suspect a number of people may have ended up at Luton/Gatwick by mistake