I wanted to drop bags early for the 18.30 BA216 last week so I could get some time at the Udvar Hazy centre. Got to IAD about 2.10pm and check in opened at 2.20pm. Was able to get the 2.33pm bus to Udvar Hazy and get a good look around.

Security was busy with the overhead sign stating 30 mins. Even with the benefit of fast track for the TSA initial screen which definitely saved some time it was still a good 20 mins to get through. First time in IAD so not sure if this is typical.