In December 1910, Ellyson was ordered to North Island, San Diego, California for instruction in aviation under Glenn Curtiss. While at an Aero Club show on 28 January 1911 near the flight school, Ellyson took off in a Curtiss "grass cutter" plane to become the first Naval aviator. With a blocked throttle, this ground plane was not supposed to fly, and Ellyson was not proficient enough to fly. He slewed off left, cracking up the plane somewhat by making a wing-first landing. However, Ellyson was not injured and from then on he was considered to have made his first flight on this date. He also cooperated with Curtiss in the design of a pontoon for aircraft, and after Curtiss' first flight on 27 January 1911, Ellyson went up with Curtiss in February to become the first passenger to go aloft in a floatplane. Later that month, he participated in experiments demonstrating the potential use of floatplanes from ships, when the aircraft was hoisted on board and subsequently lowered to the water for its return flight to North Island.