<a href="https://en.wikipedia.org/wiki/George_VI_of_the_United_Kingdom" class="extiw" title="w:George VI of the United Kingdom">HRH Prince Albert</a> at the Independent Air Force Dinner on 14 July 1919 at the Savoy Hotel, London.  Albert is wearing the insignia of the rank of captain.
Unknown author<span style="display: none;">Unknown author</span>
Flight magazine archives (<a rel="nofollow" class="external free" href="http://www.flightglobal.com/pdfarchive/view/1919/1919%20-%200814.html">http://www.flightglobal.com/pdfarchive/view/1919/1919%20-%200814.html</a>), also published in Boyle's biography Trenchard Man of Vision (plate facing p. 320).