I agree with the above, the airline isn't that "clever". For undeparted mainline flights today currently delayed by 2.5 - 3.5 hours, there's no cluster just below 3h:
Code:
estimated_delay | flights
-----------------+-------
02:30:00 | 2
02:31:00 | 1
02:32:00 | 1
02:34:00 | 2
02:35:00 | 1
02:36:00 | 1
02:38:00 | 2
02:43:00 | 1
02:45:00 | 2
02:49:00 | 1
02:50:00 | 3
02:54:00 | 1
02:55:00 | 1
02:57:00 | 1
03:00:00 | 3
03:01:00 | 2
03:06:00 | 1
03:10:00 | 2
03:11:00 | 1
03:16:00 | 2
03:17:00 | 1
03:18:00 | 2
03:23:00 | 1
03:25:00 | 3
03:30:00 | 4