All three hotels, I stayed, in Arlington offered free transportation by hotel shuttle (van or bus) at least to the nearest metro station, two of them to the nearest airport that is Ronald Reagan National Airport. Are there any hotel with no shuttle service in Arlington? Probably not. Sometimes two or more hotels located close one to each other offer together one shuttle service to share and lower the cost (Best Western and Comfort Inn on my picture). Shuttle are well signed by a logo of a hotel.
Before you book a room check on your hotel webpage whether it offer free shuttle service or call them to ask for the details like the schedule of the shuttle. The shuttles went usually every hour or half an hour and operated from early morning till late evening (10.00 or 11.00 pm).

