Very early and unusual engine brochure, WASP & HORNET on the Highways of the Sky. 19 pages, photo illus, features Ford and Fokker Tri-Motors, Hamilton and Sikorsky seaplanes; and USN Martin and Vought Corsair aircraft. Interesting trapezoid format with centerfold folding cutout (see photos) showing company logo superimposed over U.S. airlines map of the United States. Folded vertically for mailing and includes original #10 envelope the pamphlet was mailed in. Very good; little rust on staples.