Comments this is a neat article, a few minor things you might like to address:
European Union is overlinked in the lead and in the "Intercosmos program" section.
You could link "Czech Ambassador to Russia" in the lead.
Instead of "current" we normally use "as of" e.g. "as of 2015..."
"1970–1995" don't normally repeat the century in a year range within the same century.
"n the Czechoslovak Air Force.[12][8] " could we order the references numerically please?
Quite a few short sentences breaks up the flow of the prose, could use smoothing, e.g. " Hana Davidová. She was the daughter of politician" could easily be made " Hana Davidová, the daughter of politician"...
I don't think it's safe to assume that our readers know what ČSLA means without expanding it first.
"was Oldřich Pelčák the other" needs a comma before the.
"and starring Remek" this is an odd way of putting it unless it's a quote, in which case it should be "starring".
" Jean-Loup Chrétien experienced t..." maybe introduce him as "the first Frenchman in space" or "French astronaut Jean-Loup..." or similar.
Minor point but ISBNs are preferred e.g. ISBN 978-0-300-14424-6.