Linthicum sits on the Baltimore Light RailLink, with three stops in the immediate area: North Linthicum, Linthicum, and BWI Business District. From any of them it's a 25-minute ride into downtown Baltimore (Camden Yards, the Inner Harbor) and about 10 minutes south to the BWI Airport terminal stop. Trains run roughly every 15-20 minutes during the day.
The BWI Trail is a paved walking and cycling loop around the airport — about 12 miles — that passes through Linthicum and is the most pleasant way to move around the area on foot or bike.