https://www.nps.gov/nr/travel/santaclara/usn.htm https://www.nps.gov/nr/travel/santaclara/usn.htm https://www.nps.gov/nr/travel/santaclara/usn.htm dirigible National Historic Register for Moffett Field https://www.nps.gov/nr/travel/santaclara/usn.htm dirigible dirigible