The basic difference (once upon a time) between an airgun and a powder gun scope is, the reticle assembly in a airgun scope can't be knocked off its pivot points (by reverse recoil). Almost all good quality scopes, air or powder, are made captive nowadays. And, most now have warranties unheard of just a few years ago.
Sort of a sidelight.... Until about the early 50s, scopes designed for very high power rifles (460 Weatherby, 458 Winchester, etc.) had fixed reticles for obvious reasons—heavy recoil!. The mounts used adjustable cones to align the scope. Mount like this, are no longer made.