The Eindecker's designer, Anthony Fokker, was Dutch. His technological leap was to synchronize the gears of the propeller and machine gun. Previously, most fighter planes possessed machine guns mounted to the side, so the guns didn't take out their own propeller or hull while firing. But the Fokker could fire right through its propellers, Boyne says, which shocked French and British pilots, who weren't accustomed to another plane attacking them head-on. Fokkers also instilled a psychological terror in ground troops--besides snipers, poison gas and artillery, they now had to worry about death from above.
Eventually, the British and French caught up to the Eindecker's monoplane design, and its reign ended in 1916. But, Boyne says, the Fokker aircraft changed the way military airplanes and their pilots were viewed. "It initiated the lethal aircraft," Boyne says.