Boeing B-17Es (serial numbers 41-2557 and 41-9182) in formation.
U.S. Air Force
circa 1942 <div style="display: none;">date QS:P,+1942-00-00T00:00:00Z/9,P1480,Q5727902</div>
<a rel="nofollow" class="external free" href="https://media.defense.gov/2006/Jun/01/2000554845/-1/-1/0/060515-F-1234S-024.JPG">https://media.defense.gov/2006/Jun/01/2000554845/-1/-1/0/060515-F-1234S-024.JPG</a> from <a rel="nofollow" class="external text" href="https://www.nationalmuseum.af.mil/Upcoming/Photos/igphoto/2000554845/">gallery page</a>.