Park and Fly IAD
 

Is anyone aware of a hotel near IAD with a Park and Fly rate that will allow me to park 2 vehicles without reserving 2 rooms?

The Holiday Inn Dulles used to allow this, but it's been some time since I've been updated on their policies. FWIW, they don't watch their parking lot closely at all, and one could easily leave a car there.

I believe the Dulles Marriott Suites still offers a park and fly rate. The hotel isn't actually on airport property, it's surrounded by a nice mall within 5 minutes of the airport. It's a really nice property.

Hilton or Hyatt likely offer something or just don't monitor their parking lots to care. I've met someone staying at the Hyatt, left my car (and theirs) and we traveled to the airport together previously. Neither of us had any issue on the return.