I feel this is another important note to make: Many departing flights out of ADD during the most busy rush-hour time (23:00 - 00:30) are often 20-45 min delayed in departure. I think it is fair to say the airport is working at over-capacity during this time of the day. Or perhaps they are just delaying departures to wait for incoming passengers on delayed flights. I have seen passengers board planes to e.g. CAN and IAD at 30-45+ min past departure times. In one case of IAD, last passenger boarded close to one hour past scheduled departure. The rest of us had the questionable pleasure of waiting on the aircraft for 90-120min after boarding before taxiing.