Hangar No. 1, the first aircraft hangar at Mills Field, was located 150 feet to the south of the original administration building. When Hangar No. 1 was completed in September 1927, the airport site was not permanently secured, and to allow for disassembly and relocation, central attach points for the hangar’s steel frame were fastened with nuts and bolts rather than rivets. Lettering on the roof identified the airport from above, while an illuminated wind vane, rotating beacon, and an arrow pointing north provided weather and navigational information to pilots. Three more hangars of similar size and construction were added in early 1928, and although they were conceived as temporary structures, Hangar No. 4 stood until 1999. ”Mills Field and the San Francisco Airport” traces the evolution of SFO from a temporary airfield to a thriving and modern transportation hub. See the exhibition, on display pre-security in the SkyTerrace, located in Terminal 2. SkyTerrace is open Friday to Monday from 10:00 a.m. to 6:00 p.m. This image was posted on October 25, 2022.