Actually, airplanes original intent in the military was surveillance.
After a while, the pilots started to use their pistols to shoot at the enemy on the ground and then they started dropping bombs, by hand, out of the open cockpit.
"Airplanes are interesting toys but of no military value."
- Marshal Ferdinand Foch [Professor of Strategy, Ecole Superieure de Guerre](circa 1911)
He was Supreme Commander of Allied forces, 1918
"Aviation is good for sport, but for the Army it is useless!"
- Marshal Ferdinand Foch
The intent with guns were the same from its conception , how they are refined and used is corrupted as men themselves.
It took 9 years from the first airplane to turn it into a killing machine. We don't have that history with the gun it is lost.
But you cannot say the intent was purely to kill people in conception. The Atomic bomb was clearly designed with the intent top kill people. But the neutron bomb was designed to specifically
to only kill living things. Perhaps we should ban them? And keep the gun at least you have somewhat a chance with them and your skill./