There are three airports that serve TMC. All are about the same distance away.
Baltimore/Washington (BWI) and Dulles (IAD) are about an hour’s drive from TMC. No public transportation available.
National/Reagan (DCA) is a little more than an hour’s drive from TMC. There is metro service on the red line from the airport to Shady Grove, the closest stop to TMC but about a 40 minute drive from TMC.
Frederick is the closest city to TMC. It is accessible by train from Washington DC but on a limited schedule.
Information about bus schedules to Frederick is available at the Maryland Transit Administration website: mta.maryland.gov.