I attended elementary school at an old school building that was a former high school. A lot of the library was left as it had been, including a rather vast (to me) science fiction section that had lots of Golden Age titles.
One that I can recall the basic story line of, but not the title of, features a boy (teenager?) and his trusty (possibly psychic?) dog in a far-future/post-apocalyptic rural setting. The main mode of transportation were flying boats (on the super dynamic cover painting they looked like a cross between a mahogany sport boat from the 40's and a Flash Gordon rocket) . The kid's hero's journey featured a giant bear (really, really giant if the cover was any indication).
Yep- flying boats, giant bear.. it wasn't exactly Moon is a Harsh Mistress.
I recall the painted cover to be fairly amazing- the giant bear standing in front of a waterfall- the kid and the dog in a flying boat (they called them 'sleds' maybe?). I've wracked my brain for the title and for some reason I think it may have had 'golden' or 'giant' in it? That might be way off base, as I've googled this plot extensively to no avail.
Any help would be greatly appreciated.