Planes were not invented for war, but used in war. When the Wright brothers flew the first plane in 1903 it wasn't thought of as a machine for war. At first it was seen as a novelty. Wing walkers and performers would do stunts with early planes and mail was delivered by plane. As with any technology eventually it may be used in war. In the civil war hot air balloons were used for reconnaissance so it was a natural progression that the biplane was created for war.
the wright brothers
about 730 planes
how many planes id germany have at start of World War 1
Go to the related link(WW 1 war planes) for a comprehensive list of WW 1 war planes
at least 1
Yes
over 100 us planes
The US built no planes in World War 1. American pilots flew French planes; Nieuports and Spads.
scouting
They were not reliable.
1
Yes lady's did fly planes in WW1, But they had less to do.