Hunk just starts laughing, because he's taller than all his friends back home except for Shiro. He doesn't care for a second how short you aren't, Prompto. He does care that his pal felt the need to call out that he wasn't that short- was the hug making him uncomfortable? That'd be terrible! So he doesn't let go quite yet, but he does loosen up a bit.

Maybe then Prompto's feet will hit the ground?

"Are... are you feeling any better?" Hunk sounds a bit uncertain as he asks the question, but he had to ask anyway. Hugs make people feel better, right? He really wanted Prompto to feel better...