Keishi Nukina recently posted a great overview of the main Washington DC area airports from a spotting perspective, following his recent visit. If you’re planning on heading there, it makes great sense to give this a read:

WASHINGTON – NATIONAL
Traffic consisting of mostly domestic narrowbodies with a couple of Air Canada Jazz mixed in. For spotting, there is an exibit hall between terminal A and B, from where you can see all movements and in the afternoon you can take nice photographs there as well.

WASHINGTON – DULLES
Spent there one day, spotting from the parking lot of the museum and Daily Garage 2, both are excelent for photos, but you will miss a couple of movements from both. Notable international traffic include Qatar Airways, Saudi and SAA.

BALTIMORE – WASHINGTON
A couple of movements from each major airline from the US, with a lot, and I mean a lot of Southwest and AirTran aircraft. If youre in the area, definitely an airport that is worth a visit for a half day or a full day. You can spot all day from the observation room located inside terminal without being bothered, but the place is not the best for photography due to being backlit almost all day.

COLLAGE PARK AIRFIELD
If youre going to Baltimore by public transport, you will most likely be on the green metro line to Greenbelt. After the University of Maryland stop sit on the right and get your camera ready. Right after the train leaves the station, there is that airfield with a couple of light aircraft parked outside, so you will be able to get a couple of new light frames by reading them off the photos you take. Was a nice surprise for me. Nothing for those who dont collect light aircraft.