When spotting in the USA, it is generally a good idea to let the authorities know that you are there and what your intentions are. In most cases, if you speak to the right person, you’ll be thanked for the information and given permission to carry on.
Here are some contact details for various airports:
Washington Dulles – contact Ops on (703) 572-2730 and you’ll be fine from the car park.
Washington National – contact dispatch on (202) 610-7515
For spotting information on nearly 70 US airports, check out our new book – Airport Spotting Guides USA