Twin Cities Air Service is an American fixed-base operator and charter airline based at Auburn, Maine and operating from Portland International Jetport, a public airport two miles (3 km) west of downtown Portland, in Cumberland County, in which state?
Maine
Portland International Jetport
Portland International Jetport (IATA: PWM, ICAO: KPWM, FAA LID: PWM) is a public airport two miles (3 km) west of downtown Portland, in Cumberland County, Maine.
 It is owned and operated by the city of Portland.
 A portion of the Jetport's property, including the main runway, is in the neighboring city of South Portland.
Twin Cities Air Service
Twin Cities Air Service is an American fixed-base operator and charter airline based at Auburn, Maine and operating from Auburn/Lewiston Municipal Airport and the Portland International Jetport.
 The airline is a certified Part 135 operator, providing on demand and commuter service, while the FBO provides 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.
Portland International Airport
Portland International Airport (IATA: PDX, ICAO: KPDX, FAA LID: PDX) is a joint civil-military airport and the largest airport in the U.S. state of Oregon, accounting for 90 percent of passenger travel and more than 95 percent of air cargo of the state.
 It is located within Portland's city limits just south of the Columbia River in Multnomah County, 6 mi by air and 12 mi by highway northeast of Downtown Portland.
 Portland International Airport is often referred to by its IATA airport code, PDX. Marshfield Municipal Airport (Massachusetts)
Marshfield Municipal Airport (ICAO: KGHG, FAA LID: GHG) , also known as George Harlow Field, is a public airport located 2 mi (3 km) east of the central business district (CBD) of Marshfield, a town in Plymouth County, Massachusetts, USA.
 The airport is owned by the Town of Marshfield and run by Shoreline Aviation, the airport's fixed-base operator (FBO).
 It has one runway (06-24), averages 50 movements per day, and has approximately 48 aircraft based on its field.
 There are four non-precision approaches to the field: two GPS and two NDB. Allentown Queen City Municipal Airport
Allentown Queen City Municipal Airport (ICAO: KXLL, FAA LID: XLL) is a public airport in Lehigh County, Pennsylvania, on Lehigh Street two miles southwest of Allentown, Pennsylvania.
 It is owned by the Lehigh-Northampton Airport Authority.
 Also known as Queen City Airport, it is home to Civil Air Patrol Squadron 805 and Lehigh Valley Aviation Services, a fixed-base operator (FBO). Wiggins Airways
Wiggins Airways is an American fixed-base operator, cargo airline, and charter airline based at Manchester, New Hampshire and operating from Manchester-Boston Regional Airport. Provo Municipal Airport
Provo Municipal Airport (IATA: PVU, ICAO: KPVU, FAA LID: PVU) is a public airport two miles (3 km) west of Provo, in Utah County, Utah.
 The airport hosts Allegiant Air flights to four airports, one in Arizona and three in California - Phoenix/Mesa Gateway Airport, Los Angeles International Airport, San Diego International Airport and Oakland International Airport.
 It is the second busiest public airport in Utah by aircraft movements, with 172,000 aircraft operations in the year ending May 2007. Cincinnati Municipal Lunken Airport
Cincinnati Municipal Airport – Lunken Field (Cincinnati Municipal Lunken Airport) (IATA: LUK, ICAO: KLUK, FAA LID: LUK) is a public airport in Cincinnati, Ohio, three miles (5 km) southeast of Downtown Cincinnati.
 It is owned by the city of Cincinnati and serves private aircraft and the fleets of local corporations.
 It serves a few commercial flights and is the second largest airport serving Cincinnati after Cincinnati/Northern Kentucky International Airport.
 It is known as Lunken Airport or Lunken Field, after Eshelby Lunken.
 It is bounded by US Route 50 (historic Columbia Parkway and Eastern Avenue) to the west, US Route 52 (Kellogg Avenue) and the Ohio River to the south, the Little Miami River (which originally flowed through the airfield but was diverted) to the east, and Ohio Route 125 (Beechmont Avenue) to the north.
 The airport is headquarters and hub for Cincinnati-based public charter airline Ultimate Air Shuttle, serving 5 destinations in the eastern United States with 16 peak daily flights.
 Lunken is also home to small charter airline Flamingo Air and its aviation school. Great Lakes Air
Great Lakes Air is an American Fixed-base Operator and charter airline based out of Mackinac County Airport in St. Ignace, Michigan. Starlink Aviation
Starlink Aviation is a Canadian fixed-base operator, passenger and charter airline.
 It is based at the Montréal-Pierre Elliott Trudeau International Airport in Montreal.
 Starlink is primarily a charter carrier, but also operates a small fleet of turboprop aircraft on scheduled "Corporate Shuttle" routes in Eastern Canada.
 Between February and November 2009 the company operated two daily flights between Portland, Maine, Yarmouth, Nova Scotia and Halifax, Nova Scotia.
 On December 1, 2009, service ceased due to depletion of the Air Service Fund.