Air Service Boys Over the Enemy's Lines; Or, The German Spy's Secret

World War, 1914-1918 -- Juvenile fiction; Aeronautics -- Juvenile fiction; World War, 1914-1918 -- Aerial operations -- Juvenile fiction; Parmly, Jack (Fictitious character) -- Juvenile fiction; Raymond, Tom (Fictitious character) -- Juvenile fiction; Air pilots, Military -- Juvenile fiction