Metrobus buses just run during the hours that there is not a Metrorail service.
The service is operated by Washington Metropolitan Area Transit Authority (WMATA).
In general, buses run during weekend mornings or before the metro service has started.
To get straight to DCA Airport, please take routes Express Airport 5A and B30.
Buses can be board in the designated stops outside Terminal A and Terminal B & C.
See below the established fares:
Local Bus: $2.00
Express Bus: $4.25
Express Airport buses 5A and B30: $7.50