History Airplanes, Military 24 Aeronautics 18 Airplanes 14 Juvenile literature 13 World War, 1939-1945 12 Firearms 11 Design and construction 10 Equipment and supplies 10 Aeronautics, Military 9 Artillery 8 Pictorial works 7 Tanks (Military science) 7 World War, 1914-1918 7 Warships 6 Fighter planes 5 Military weapons 5 Machine guns 4 Management 4 Naval aviation 4 Pistols 4 Rifles 4 Arms and armor 3 Battleships 3 Biography 3 Military 3 Naval history 3 Tank warfare 3 18th century 2 Aerial operations, British 2