Previous editions of the «Virtual Airplane» book (as PDF-file) licensed under "CC-BY-NC-ND", where Polish version is free to download, and you may buy English version to support Witold (+ pay PL-to-EN translators work).
Also "CC-BY-NC-ND" allows You to create commercial airplanes 3D models, but redistribution or modification of book itself is not permitted (at least without Witold's permission).
Few years ago I contacted with Witold via e-mail & asked him for give me permission to translate 1st Edition[0] of this book (which was written for Blender 2.4x) from Polish to Ukrainian under "CC-BY-NC-ND" — as result he provided me a DOC-file (book draft) ;)
JFTR, I'm still a happy user of Blender 2.49b[1,2] ;P
