Causes of the War .The underlying causes of World War I were the spirit of intense nationalism that permeated Europe throughout the 19th and into the 20th century, the political and economic rivalry among the nations, and the establishment and maintenance in Europe after 1871 of large armaments and of two hostile military alliances. World War I
provided a great stimulus to the production and military use of aircraft, including the airplane and airship, or dirigible balloon, and the tethered balloon. Aircraft were used for two principal purposes: observation and bombing. For observation of stationary battlefronts extensive use was made by both belligerents of small tethered balloons; for scouting at sea, dirigible balloons were extensively used, and airplanes were used for scouting coastal waters.
