#Yes and no There's no reason why not, apart from the fact that beaks became dominant to the point of exclusion for a reason. To have a toothed flyer your world could be at a much earlier stage of an evolutionary cycle, perhaps not long after a mass extinction event when there were a lot of broad niches to be refilled and a lower pressure to be perfectly optimised. It may not be a particularly efficient flyer, but it can fly. Size wise, that's a question for consideration but a mating tendency towards "biggest and strongest" could make for a big creature. In the long run the efficiency and lighter weight of the beaked flyers would likely come to dominate and displace your overweight creatures.