currently, the worlds largest reptile is the saltwater or estuarine crocodile. they can reach up to 20 feet max
Alligators and crocodiles are the largest living reptiles.
That kind of a question is only put up from a child. For your question, there are no known flying reptiles, unless you mean in the time of dinosaurs where a few dinos could glide.
Pteranodon
no but there r gliding ones