Here are entered works on military aerial observation in general, including aerial reconnaissance and surveillance, monitoring of friendly ground forces, observation of friendly artillery fire, etc. Works limited to the aerial examination of enemy territory to obtain military information concerning installations, movements, resources, strength, etc., are entered under Aerial reconnaissance.
--subdivision Aviation under navies, e.g. United States. Navy--Aviation; and subdivision Aerial operations under wars, e.g. World War, 1939-1945--Aerial operations