Sukhoi: a comment and a question:
The comment is that Russian aircraft usually look odd. I have always believed a plane that looks good will fly good. Soviet aircraft usually look like something out of a 1940’s Flash Gordon comic book, BUT the Su-27 is a beautiful exception. (Opinion, obviously)
The question is “Why did Tolkachev do it?” Surely, it wasn’t simply for the money.
Oldplayer
The aircraft also have the odd shade of blue and green colors.
This article (long but interesting) says it was anger against Soviet actions.
http://www.theatlantic.com/international/archive/2015/08/adolf-tolkachev-cia-kgb/400769/