I took these pictures during the beginning of a flight from Paris to Washington DC on the 18th of September. It shows the subanthelic area. At first the subanthelion appeared alone ( 1 ).
Then a short time later subparhelic circle and diffused arcs appeared too for about 1 minute ( 2 ).
Later on the flight, I could observe some brightening in the subanthelic area but not as conspicuous as in the beginning of the flight