Airplanes, Military 109 History 95 Management 94 Handbooks, manuals, etc 92 Periodicals 91 Dictionaries 78 Airplanes 67 Fighter planes 47 Firearms 40 Strategic planning 31 Encyclopedias 29 Maintenance and repair 28 Pistols 28 Aeronautics 27 Quality control 27 Medicine 25 World War, 1939-1945 25 Industrial management 24 Personnel management 23 Warships 23 Ordnance 21 Training of 21 Artillery 20 Employees 20 Equipment and supplies 20 Design and construction 19 Weapon systems 19 Automobiles 17 Marketing 17 Research 17