10 books • 1 series
The Airplane Boys
Flying to Amy Ran Fastness
Airplane Boys at Cap Rock
Airplane Boys in the Black Woods (Airplane Boys)
Airplane Boys on the Border Line (Airplane Boys)
Airplane Boys with the Revolutionists in Bolivia (Airplane Boys)
Airplane Boys Discover the Secrets of Cuzco (Airplane Boys)
Airplane Boys Flying to Amy-Ran Fastness (Airplane Boys)
Airplane Boys at Belize (Airplane Boys)
Airplane Boys at Platinum River (Airplane Boys)