Hello, I would like to share with you a link to a web site with photos of Sky-Busters made in Bulgaria.
I do not know the history behind these toys, but the castings are very different from those of the "Matchbox" Series that Lesney introduced in 1973.
In particular, note the MiG 23 with swing wings, a Polikarpov biplane, a Tu-144, and a space shuttle named "Buran."
http://www.bulgariancollection.com/matc ... lgaria.htm
I remember once seeing photos of an abandoned factory, somewhere in Bulgaria, in which toys like these were made, allegedly. The name was Micro which in cyrillic alphabet looks like "Mukpo" written in script: Mикро. It is quite possible that Bulgarians created these toys by altering the molds for the Swing Wing Jet (1-75 series, not Sky-Busters), the Pitts Special (SB-12-B), the "Supersonic Transport" (i.e. Concorde SB-23) and the US space shuttle (SB-03-B) respectively.
The casting for the first toy shown appears to be same as the Matchbox issue MiG-21.