Found in 2 comments on Hacker News
schlomie · 2011-04-25
· Original
thread
Some of those look pretty similar to ones I recall making from this book as a child:
http://www.amazon.com/Great-International-Paper-Airplane-Boo...
https://www.amazon.com/dp/0671211293?tag=duckduckgo-osx-20&l...
The 70's truly were a creative decade....
A seemingly related book is on archive.org, the helicopter appears to be on page 38:
https://archive.org/details/The_Great_International_Paper_Ai...