Question: Martha's Vineyard Airport and Erie International Airport, are which class of airport?
Context: The Niagara Frontier Transportation Authority (NFTA) is a public authority responsible for the public transportation oversight of Erie and Niagara counties in the state of New York.  The NFTA, as an authority, oversees a number of subsidiaries, including the NFTA Metro bus and rail system, the Buffalo-Niagara International Airport, the Niagara Falls International Airport and NFTA Small Boat Harbor.  The NFTA Metro bus and rail system is a multi-modal agency, utilizing various vehicle modes (diesel bus, diesel-hybrid bus, CNG bus, light rail and cut-away van), using the brand names: NFTA Metro Bus, NFTA Metro Rail, NFTA Metrolink and NFTA PAL (Para-transit Access Line).  In addition, the NFTA also owns and manages a number of properties, including the Buffalo Metropolitan Transportation Center in Downtown Buffalo (which serves as the agency's headquarters); the Niagara Falls Transportation Center on Factory Outlet Blvd. the Portage Road Transit Center in Niagara Falls; and a number of strategically located bus loops and transit centers in the Buffalo Niagara region.  Of note, many of the bus loops have been in continuous operation since the days of the International Railway Company, a predecessor to the NFTA.  Agency-wide, the NFTA employs 1,500 full-time and part-time employees.  There are three business centers that operate as the NFTA organization: Surface Transportation, which handles ground transportation throughout Erie and Niagara counties, Aviation, which handles air related business at the Buffalo-Niagara International Airport and Niagara Falls International Airport and Property Risk/Management, which operates the NFTA-Boat Harbor and handles other properties that are owned and/or operated by the NFTA. Pennsylvania Route 299 (PA 299) is a 0.05 mi state highway located in Erie County in Pennsylvania.  The route is the designation for the Staff Sergeant Jeremy R. Horton Memorial Bridge that carries Powell Avenue over two railroad lines in Millcreek Township.  PA 299 was designated in 1930 between US 20 and PA 99, which is now PA 5 Alternate (PA 5 Alt.) , running along Powell Avenue.  In 2006, the current bridge over the railroad tracks was built.  In 2011, all of PA 299 was decommissioned except for the Staff Sergeant Jeremy R. Horton Memorial Bridge, and is no longer signed as a traffic route.  The section of Powell Avenue north of the bridge was realigned in 2012 as a result of runway expansion at Erie International Airport United p.s. is a premium service offered by United Airlines on flights between Newark Liberty International Airport and Los Angeles International Airport and San Francisco International Airport, as well as between Boston Logan International Airport and San Francisco International Airport.  The fleet consists of specially configured Boeing 757-200 aircraft with three classes of service: United Business, United Economy Plus, and United Economy.  Each class of service includes certain amenities not offered on regular flights. MVY is the IATA airport code for Martha's Vineyard Airport. Erie International Airport Tom Ridge Field (IATA: ERI, ICAO: KERI, FAA LID: ERI) is a public airport five miles (8 km) southwest of Erie, in Erie County.  Airline service at Erie faces stiff competition from the Pittsburgh, Cleveland and Buffalo airports, all within two hours of Erie by car.  In 2004 Erie was the third fastest growing airport in the United States, and the fastest growing airport in Pennsylvania.  It is also 128 mi from Pittsburgh, 111 mi from the Canada–US border, 95 mi from Cleveland, Ohio and 105 mi from Buffalo, New York. Martha's Vineyard Airport (IATA: MVY, ICAO: KMVY, FAA LID: MVY) is a public airport located in the middle of the island of Martha's Vineyard, three miles (5 km) south of the central business district of Vineyard Haven, in Dukes County, Massachusetts, United States.  This airport is owned by Dukes County and lies on the border between the towns of West Tisbury and Edgartown.  It is often used for general aviation but is also served by four commercial airlines. On July 16, 1999, John F. Kennedy Jr. died when the airplane he was piloting crashed into the Atlantic Ocean off the coast of Martha's Vineyard, Massachusetts.  The two passengers on board, Kennedy's wife Carolyn Bessette and her sister Lauren, were also killed.  The Piper Saratoga light aircraft had departed from Essex County Airport in Fairfield, New Jersey, and its intended route was along the coastline of Connecticut and across Rhode Island Sound to Martha's Vineyard Airport. Manuel F. Correllus State Forest is a Massachusetts state forest located on Martha's Vineyard.  The forest borders Martha's Vineyard Airport on three sides and is chiefly in the towns of West Tisbury and Edgartown.  The forest is managed by the Department of Conservation and Recreation. Mayflower Airlines was a small regional airline in the United States that operated out of two airports, the East Boston Airport (now known as Logan International Airport) in 1936, and the New Bedford Airport.  Flights were in Ford Tri-Motor "Clippers" and covered Cape Cod (Hyannis, Provincetown) and the Islands (Nantucket and Martha's Vineyard).  Service was also provided to Springfield, Massachusetts, as well, with fares that ranged from $5.00 to $8.00.  Daily scheduled service was provided from Boston and New Bedford.  Providence R.I. is also listed as a departure point to the Islands without scheduled service.  The company was absorbed by NorthEast Airlines in 1945.  Timetables for the airline still exist and list destinations and fares. The Town of Erie is a Statutory Town in Boulder and Weld counties in the U.S. state of Colorado.  The population as of the 2010 census was 18,135, up from 6,291 at the 2000 census.  Erie is located just west of Interstate 25, with easy access to Interstate 70, Denver International Airport and Colorado's entire Front Range.  Erie's Planning Area spans 48 sqmi , extending from the north side of State Highway 52 south to State Highway 7, and between US 287 on the west and Interstate 25 to the east.  Erie is approximately 35 minutes from Denver International Airport, 25 minutes from Denver and 20 minutes from Boulder.
Answer: public