Question: Petersburg James A. Johnson Airport and Nantucket Memorial Airport, are which specific type of airport?
Sentence (from "Nantucket Memorial Airport"): Nantucket Memorial Airport (IATA: ACK, ICAO: KACK, FAA LID: ACK) is a public airport on the south side of the island of Nantucket in the U.S. state of Massachusetts.
Relevant evidence: Yes