Air Service Boys Over the Enemy's Lines; Or, The German Spy's Secret
World War, 1914-1918 -- Juvenile fictionAeronautics -- Juvenile fictionWorld War, 1914-1918 -- Aerial operations -- Juvenile fictionParmly, Jack (Fictitious character) -- Juvenile fictionRaymond, Tom (Fictitious character) -- Juvenile fictionAir pilots, Military -- Juvenile fictionPZ