The author describes the Air-Service work at McCook Field, presenting and describing numerous types of airplane, airplane engine and auxiliary aviation apparatus. After reviewing the development and present status of the Air Service, he describes the airplanes developed during the war and comments briefly upon their chief characteristics, referring to the illustrations; airplane engines are treated in a similar manner.
Among auxiliaries, mention is made of airplane armament, synchronizing outfits, parachutes and packs, machine-guns, bombs, cameras and photographic equipment, with comment upon their usage and characteristic features. Armored airplanes are considered specifically and the use of variable-pitch propellers exemplified. The relations of military and commercial aviation are stated and the possibilities of airplane transport and airplane hospital ambulance service are mentioned.