20 hours? Depends on what you count as delay. Was diverted to Lafayette, LA on a MIA-IAH flight and had to wait hours on the tarmac as they figured out how to get us off the plane. Maybe 2 or 3 hours. Ended up being escorted by Sheriff's and EMTs unto tarmac and into back door of airport, apparently there were no gates or AA employees to handle our unexpected arrival. Got to IAH about 20 hours later.

Also been delayed for a few hours on an AA 772 back when they had F, after a couple of hours on plane but at gate they canceled flight. Everyone off plane and trying to rebook, didn't get to AA provided hotel until 3 or 4 am. Missed 1 day of vacation.