He couldn't fathom it; who in their right mind would forego the advantage of wings by choice? The boy's father is an idiot, but he wouldn't say that out loud.
Then the boy introduces himself as Malachi, and Matthias takes a better look at the wings now that they've been better cleaned off and pruned. Fortunately, their wings were quite similar - vulture to falcon, both birds of prey. But he also knew there would be some marked differences. He takes his eyes away from the wings for a moment and back to Malachi to respond back. The subtle snarkiness that came about by Malachi finishing his answer with the same question was not lost to Matthias. His brows would crease just slightly, "You'll come to notice, if you haven't already, that a lot of things are transactional, including relationships. If you can't offer anything good in return for learning how to fly, then nobody is going to bother wasting time trying to teach you to fly," his own words came out a hint more serious, but lacked any sort of condescending tone, "And learning how to fly, if you have the means to, can benefit you in a lot of ways your father probably failed to mention. Imagine being able to go from place to place faster. Being able to avoid any danger on the ground, any harsh terrain. Imagine how much more efficient you can be at hunting, pouncing on your prey from above. And fighting, too! Your melee opponens are going to have a rough time hitting a target who's in the air."
It was then that the lion would step further away from the edge of the cliff. His own wings remained outstretched. After a moment of consideration, he'd say, "I could always use more resources. I'll tell you what, if you can drop off the leftovers of your hunts: clean pelts, feathers, any body parts of interest like rabbit feet, talons, teeth, eyes, that kind of stuff, then I'll keep teaching you how to use those wings for as long as you provide these things, or until you think you can handle the rest on your own. Deal?" he'd outstretch a wing, the primary feathers at the end tilted outwards as a sort of stand-in for a pawshake.