WATCH: Pilots pay tribute to three Ohio guards killed in Iraq refueling plane crash

An aviation enthusiast has paid a touching tribute to three members of the Ohio Air National Guard who were among six service members killed in a tanker accident in western Iraq just days ago.Flight tracking data from Flightradar24 shows that on March 19, a pilot made a symbolic salute in the sky, tracing the outline of a service member along three headstones to honor fallen Ohio Guardsmen.According to U.S. Central Command, Capt. Seth Koval, Capt. Curtis Angost and Master Sgt. Tyler Simmons were participating in the U.S. government’s Operation Epic Fury on March 12 when a KC-135 aircraft crashed around 2 p.m. The military said the plane lost contact while flying over friendly airspace and the cause of the crash was still under investigation.Maj. John Alex Klingner of Auburn, Alabama, was also killed in the incident. Capt. Ariana G. Savino, Covington, Wash.; and Technical Sergeant Ashley B. Pruitt, Bardstown, Ky. The Ohio National Guard and the 121st Air Refueling Wing later paid tribute to Koval, Angst and Simmons, BBC News reported.In just 21 days of conflict, at least 16 military aircraft – 12 drones and four aircraft, including the THAAD radar system, an F-35 stealth fighter and even the USS Gerald R. Ford – were involved, although not all incidents were directly caused by enemy fire.In early March, three F-15 fighter jets were shot down in “an apparent friendly fire incident” over Kuwait, officials said. All six crew members ejected safely. Boeing built the KC-135 Stratotanker for the U.S. military in the 1950s and early 1960s.It has been the backbone of the U.S. military’s aerial refueling fleet, allowing fighter jets to fly longer missions without landing.