Cape air marion il Cape Air Service, Inc doing business as Cape Air has its main office at Barnstable Municipal Airport in Barnstable, Massachusetts, in the United States. The was founded in 1989. It operates regular passenger flights to the Northeast, the Caribbean, the Midwest, Eastern Montana, and Micronesia. Flights to Micronesia are operated as United Express flights thanks to a code-share arrangement with United Airlines. You can also use the Cape Air Offices' contact information and flight booking, alteration, and cancellation instructions.