system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Can Juggernaut fly? If not, why not?

Can't he just use his "can't be stopped unless he wants to be" power after jumping?

I get that the Hulk can slow him down, so gravity should be able to as well, but an enraged hulk >>>>>>> the Earth's gravitational field.

Hell, Juggernaut should theoretically be able to fly (albeit somewhat awkwardly while he got used to the process) by flapping his arms while in the air, right?
gpt
It isn't as if the power is that once in motion his inertia is infinite making it impossible to stop him. His ability to keep moving requires him to propel himself forward, something he can't do because he has no traction on air. He also can not walk on water; he sinks because the density of water is no sufficient to support him. Same is true for the air.