If the the body and it's wing is mostly covered with solar panels and flies with electric motors, is it possible for that aircraft to fly?
Not a stupid question at all! This was one of the goals that solar impulse I and II set out to show. one thing to keep in mind is that its of course only possible while the sun is shining. It was able to do it but the margin of error was fairly small,


  During the day, the plane flies only by the energy from the sun. But
  in the morning and evening, when sunshine is not so strong, and
  especially at night, it must tap into its reserve of energy stored in
  its batteries. So every evening, the pilot must make sure that the
  plane’s batteries are 100% charged so that it can fly until the next
  sunrise.


Solar impulse ran on 8HP motors which is not much more than the Wrights first powered aircraft with a cruise speed of 56MPH it was not a terribly fast aircraft either but proved the concept was possible at a small edge of the spectrum.