Change of guards: a U.S. Navy Lockheed P-2H <i>Neptune</i> and its successor, the Lockheed P-3A <i>Orion</i> (nearer to the camera), in 1963.
USN
U.S. Navy Naval Aviation News June 1963 <a rel="nofollow" class="external autonumber" href="http://www.history.navy.mil/nan/backissues/1960s/1963/Jun63.pdf">[1]</a>; <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/127906254@N06/16668570906/in/album-72157650713449190/">National Museum of the United States Navy</a> photo, NHHC Photograph Collection, Aviation, L-File, P-3, Orion.