This map depicts the corridor for flight navigation between Phoenix, Arizona, and San Diego, California, including major urban areas, roads,... Show moreThis map depicts the corridor for flight navigation between Phoenix, Arizona, and San Diego, California, including major urban areas, roads, railroads, etc., and the location of airfields and navigation beacons. It was compiled and produced by the Engineer Reproduction Plant, Corps of Engineers under the direction of the Airways Section, Office Chief of the Air Corps in 1931. Show less