Where possible, images are used that tie directly to the story: the exact aircraft or location. Otherwise, photos were secured that fit the narrative for some particularly illustrative purpose. Where necessary, expressed permission was obtained from the photographers or by agreement with similarly generous contributors to the Creative Commons or other shared media sites.

Captions with links point to either the source of the photograph or, in some cases, to a website favored by the photographer. Other links are provided for examining the licensing agreements governing use of the work.