What were two different roles that the airplane served during wwi? explain each.

For the military the airplane provided reconnaissance information to ground forces to they could plan an attack based on enemy positions. Eventually this evolved to putting machine guns on the planes so they could also aid in an attack from the air.
Airplanes were also used for humanitarian missions such as the Belgian food drops orchestrated by H.Hoover. Airplanes were able to drop medical and food supplies behind enemy lines ensuring no shortages of supplies by troops. Additionally, civilians were given supplies despite being in enemy territory or being the victims of an economic blockade. 

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