"If it was easy, someone else would've done it..." Another one of these threads. I just ran through the gamut with an aeronautics grad student friend of mine - we spent a good 8 hours discussing and researching a myriad of ideas - and everything we did turned up short. We tried all plastic structures; but no luck, nothing had a good enough strength to weight ratio. We tried all plastic structures with aluminum spars; no luck, same problem, and it was just too heavy overall. We tried thermoformed plastic with carbon fibre or fiberglass insets as strengtheners; the labor costs required in piecing it all together and trimming/fitting those composite strips would make the other labor savings negligible. We tried a hershey bar wing that was literally just an extruded aluminum shape; this was OK, but we found a lot of difficulties attaching the wing to anything else. This was probably our best option though - but still expensive. Fiberglass has it's obvious limitations, as does welded/rivited aluminum. I'm really beginning to think that a manufactured airplane below $50,000 really is just a pipe dream for people who don't really know the nitty gritty of aircraft design. The more I learn, the more I realize just why this hasn't been done before. How about you guys? Any ideas?