His complete body was never recovered but about a week later he was declared as having been killed in action following DNA tests on remains found in the wreckage of his aircraft.
"His body was removed from the crash site by anti-coalition personnel before US forces could arrive to secure the area," the air force said overnight.
This week the so-called Islamic State in Iraq, an umbrella organisation of Sunni insurgent groups in Iraq, released an image of Gilbert's US military "Geneva Conventions Identification Card" on an Internet site.
A statement accompanying the image of the card - issued to US servicemen in Iraq - said the group would shortly release a video entitled The Missing.
"We are aware of the attempts by anti-coalition forces to exploit Major Gilbert's death," said Lieutenant General Gary North, commander of United States Central Command Air Forces.
"It is appalling and cowardly that they did not treat his remains with the respect deserved of an honourable warrior," he added.
Gilbert had been based in Balad airbase in central Iraq as part of the 332nd Aur Expeditionary Wing, part of the 140,000-strong US military force in Iraq. news.com.au