Twin Cities Air Service was an American fixed-base operator and charter airline based at Auburn, Maine and operated from Auburn/Lewiston Municipal Airport and the Portland International Jetport. The airline was a certified Part 135 operator, provided on demand and commuter service, while the FBO provided standard aircraft services and maintenance, specializing in overhauls of the Cessna 400 series aircraft. Beginning in March 2010, Twin Cities Air Service began a scheduled commuter route between Portland, Maine, and Yarmouth, Nova Scotia. At the time of the initiation of this route, Twin Cities was the only scheduled carrier into the Yarmouth Airport, and was the only scheduled international service into the Portland International Jetport.