Which Wright brother was the first to fly the 1903 Flyer?

Orville Wright was the first to fly the 1903 Flyer.

On December 17, 1903, Orville lay prone on the lower wing and operated the aircraft during the first powered flight at Kill Devil Hills. The flight lasted 12 seconds and covered 120 feet. The brothers had agreed to alternate flying turns after an earlier attempt by Wilbur on December 14 ended in a stall soon after takeoff.

Wilbur then flew the second attempt, while Orville piloted the third and Wilbur the fourth. Their arrangement allowed both brothers to test the aircraft and share responsibility for the breakthrough.

The first flight was brief and difficult to control, but it proved that a heavier-than-air machine could take off under its own power and remain airborne under pilot control. The Flyer was later damaged by wind after the fourth flight.