1. Know your rights
Keep the timing in mind. Know what rights you have after the delay reaches an hour (Europe). At this point it is a good idea to take a look at your airline’s contract of carriage for details of their policy.
2. Take action
Are you being offered water? Are the flight attendants keeping you informed of the situation? If not, kindly remind them that this is your right. If the tarmac delay extends beyond a few hours you should be given the option to de-plane (US). If not, the airline is not complying with the law. The airline can only keep you on the plane if it’s for safety reasons, or if facilitating departure would cause disruption of airport services.
It’s important to note that an airline is under no obligation to let you back in if you decide to disembark.
3. Not Satisfied?
If you end up in a situation where the airline isn't complying with the law, file a complaint. In the US: you can contact the airline via email or mail; the airline has up to 60 days to respond. If the airline does not respond or if you are unsatisfied, you can register a complaint with The Department of Transportation.