Thank you to Jon Proctor for contributing this great image of a National Electra on Concourse 3 (now F) at MIA. He took the photo from the public observation deck on top of Concourse 4 (renamed to E in the mid 70's).

Jon says that this aircraft flew less than four years with American Airlines before it was sold to National and re-registered as N5017K. This aircraft has unique (to AA and WA Electras) small porthole lavatory windows in the fuselage just above the "L" in the National titles.