Go look at bricklink.com sets from around the 1970's. They were ALL just a bunch of blocks. An airplane was basically a long rectangle. Then the 80's brought in some really nice "Legoland" sets. The lego airport from that era was the sweet spot. Not too many specialized pieces, but enough to build proper airplanes and a control tower.
That said, if you want large sets of generic pieces look into a creator bucket. They come out to something like 5-10 cents a piece and sound like what you are talking about. They're fairly new so I haven't used/bought them, but I think they're basically the same thing as the 'basic' buckets I had as a child.