Time-Lapse video of the “Boneyard”. The 309th Aerospace Maintenance and Regeneration Group at Davis-Monthan Air Force Base, Arizona, contains about 5,000 retired military aircraft, which makes it the largest aircraft storage and preservation facility in the world. Crews at the Boneyard preserve aircraft for possible future use, pull aircraft parts to supply to the field, and perform depot-level maintenance and aircraft regeneration in support of Air Force operations.