If evolution is true, where did flying creatures come from?

Say we have a seed that has never flown before and has no instincts at all. It may have a deformity, a bit of fluff or a flap, which is quite ugly to the other seeds. But that deformity allows it to glide or parachute farther from the tree than its seed-siblings. Maybe it glides closer to the water, where it has a better chance of growing bigger and stronger and having bigger and stronger offspring.(I'll leave it to the smart people to tell us whether plants invented flight before or after animals.)

No. They crawled, slithered, oozed, flopped and eventually flew because they could. In some cases the ability to crawl, slither, ooze, flop and fly was beneficial to survival and was passed on to their descendants; in other cases maybe not.The ability to distinguish good ideas from bad is a separate line of evolution. Our species manages to survive even though some individuals lack that ability.