Aeronautical
Bob Steele Afloat in the Clouds; or, The Boy Who Owned an AirshipBob Steele's Last Flight; or, The Sale of the Comet
Bob Steele's New Aeroplane; or, The Bird Man
Aircraft
Bob Steele From Auto to Airship; or, A Strange Adventure in the AirMotor Boating
Bob Steele's Motor Boat; or, The Fellow They Could Not BeatMotorcycling
Bob Steele on High Gear; or, A Prize Worth WinningBob Steele's Motor Cycle; or, True to His Friends
Sea -- Submarine
Bob Steele in Strange Waters; or, Aboard a Strange CraftBob Steele's Submarine Cruise; or, Captain Nemo's Friend