For me, it was "The Great International Paper Airplane Book" (which I was happy to discover is now available for borrowing on the Internet Archive): https://ar

For me, it was "The Great International Paper Airplane Book" (which I was happy to discover is now available for borrowing on the Internet Archive): https://archive.org/details/greatinternation00jerr https://archive.org/details/greatinternation00jerr I went through 2 physical copies cutting out all the patterns to make the various planes.