I would try going into the flight in a default aircraft, switching to the B-17 and then saving that flight (as default if you like).
Then next time you want to fly, load that saved flight. Problem should be fixed.
I'm not sure I would mess around with saving the B-17 as the default flight, even if you had previously loaded up a default aircraft.
If it were me, I would load up the Cessna, save it as the default flight, and from then on out, load the B-17 and any other airplane you fly from the Free Flight GUI.
I can load a default FSX plane (DC-3) then "switch" to the B-17, and that works. I did set a B-17 as my "Default" plane (I had it that way before in both FS9 and FSX), but that does not work, now.
I have never needed to load a default plane before, so I believe there is a proper solution to this problem.
I am seeking the info that will correct my current problem.
Thanks for your replies.