Question #1 - "flight" is when "the aircraft moves under its own power". So tell me how exactly can an unpowered craft ever undertake a "flight"?
That looks more like you are quoting the rules for logging of flight time, not the definition of flight in itself. Law does not have to define something that is general knowledge, ie everyone knows that flight is the act of flying, applied to any object. You will not be able to twist any legal fraternity on what is flight, any 'thing' can be launched or power itself into flight. A bird, insect or thrown rock can take flight. If you are quoting the flight time definition it quite clearly states for the purpose of that section.
Question #2 - "aircraft" is "a craft that derives support from reactions* of the air". So why would such alternative methods of lift make it an "aircraft" exactly?
Fair enough I was exaggeration on the sci-fi stuff, however that does not change what we are talking about in this. A hang-glider uses air to stay aloft, so it is an aircraft. Same with model aircraft. Unless your vehicles have cracked physics problems and are powered by antigrav then you are buggered. Then possibly another set of rules will be 'created', as for now it is what it is.