Check-in line was huge and I missed my flight. Whose fault is it?

If you arrived within the airline’s recommended time, you have a stronger case. Here is what I’d try:

1. Tell a staff member early that your flight is about to close. Airlines sometimes help passengers in long lines.
2. Go to the desk and calmly explain that you arrived on time.
3. Ask for rebooking and a waiver of change fees.
4. Keep proof, such as your arrival time and photos of the queue.
5. Use online check-in and bag drop next time to skip lines.

Airlines don’t always take responsibility, but evidence helps. This guide on what to do if you miss your flight has more.