@Umami Stale  
Events in the show basically support this headcanon. When Tirek went around pulling magic out of ponies, the pegasi stopped being able to fly, and the earth ponies just sort of sat down and did nothing because they’d lost their ability to tend to the land.

@Background Pony #E7BC  
Actually, I can explain this through the power of headcanon!
 
See, I think that every race of pony has their own sort of magic. For Unicorns it’s, well, obvious. They learn spells yadda yadda ya. For earth ponies, they’re in tune with nature to a degree that the other races can’t really understand. This is thanks to a sort of latent earth magic within them. It lets them be more in touch with nature, tend to crops better, stuff like that. As for Pegasi, rather than deal with the fragility that would come with something like hollow bones or the like (Especially given the crashes we’ve seen some of them go through), I prefer to think they have an inner ‘flight magic’ that lets their wings carry them. So, while Umi is a massive pony, more in line with a draft horse really, his wings are still proportionate to his body size. Not really oversized, but rather fitting for his form.

@Background Pony #E7BC Pony #5F01”:/1007373#comment_4612854  
considering he is so big, he probably has an immense wingspan. I mean look at the dragons in their universe, they get off the ground.

I’m getting the impression that he is one of those people that are the size of a bear in every way.

More than a ton? Is it even safe to share a bed with him? What if he rolls over on you?

@Dragon-Commando  
Apparently, he also weighs more than a ton.  
Good luck getting much use out of those wings, fatass!

7 feet tall? he’s huge next to other ponies.

Kind of wish if MLP:FiM ponies were real they’d be that size. Probably better to cuddle than horses.