On October 5, 1914, the World War I first aerial combat resulting in a kill took place. From the article:
"By the time World War I began in the autumn of 1914, airplane engineers and pilots had been thinking about aerial combat for years, even if nobody had yet seen what would later be called a dogfight.
Aviation historian Harry Woodman considered a 1913 incident from the Mexican Revolution to be the “first aerial duel in history between two airplanes.” American pilots Phil Rader and Dean Ivan Lamb, who were on opposite sides of the conflict, fired revolvers at each other while airborne. Neither one got hit.
The first aerial battles of World War I were variations on that same theme. French aviation historian David Méchin ticks off a list of “firsts” that all happened within a few weeks of each other in 1914. On August 25, Roland Garros and Lt. de Bernis became the first flyers to damage an enemy aircraft. Flying a Morane Parasol, they shot at a German airplane, which escaped in a dive, although one of the two men onboard was wounded. On September 7, Russian Pyotr Nesterov was the first pilot to destroy an enemy airplane, but he did it by ramming his Morane into an Austrian Albatros. Both air crews died as a result.
Then, on October 5—100 years ago tomorrow—French pilot Sgt. Joseph Frantz and his mechanic/gunner, Louis Quénault, shot down a German biplane near Reims to record what is considered the first official aerial combat victory. Méchin tells the story in detail in this month’s edition of the French aviation history magazine Le Fana de l’aviation."