The fact that we don't have wings would be a good start.
Domesticated turkeys are generally unable to fly due to selective breeding for increased chest muscle mass. This additional muscle weight makes them too heavy to be able to fly.
No, the wizards of Lord of the Rings are unable to fly.
kiwi
anteaters are unable to fly because they do not have bones like a bird and they do not have feathers or wings to catch the air and glide
No, Snipes cannot fly. They are ground-dwelling birds with making them unable to fly.
No, all normal ladybugs are able to fly.
You are unable to fly airplanes, however you can fly helicopters.
Flightless.
Yes. I mean they can't fly. But they swim in a motion similar to flying
I have no wings, hence I am unable to fly.
It will likely be unable to fly, and will probably die.
no