some are disgned to fly. others are said that they can fly but really can't.i attempted the su-34 a year ago with 80 gram paper and it turned out good without reinforcements.once i made f-22 out of the 80 gram paper and realize that it had some weak points around the frontal fusalage. so what i did is that i printed out another two more. one for the body,other for rienforcent, and i glue them together at the weak spots and a significent change has happend with its strength . the models it pretty well made itself even when printed on the weaker paper sometimes, so i suggest for you to make a test model,find the problems, and try to fix then if you can