I finally found it!
I saw a badly dubbed english version of this when I was a kid and loved it! Been searching for it on the internet forever.
It's never over, all my blood for the sweetness of his laughter
I found this title with english subtitles available from http://www.ebay.com/itm/O-princezne-Jasnence-a-letajicim-sevci-DVD-1987-Czech-Fairy-tale-English-subs-/131155017895?hash=item1e8972c0a7
this dvd is also available from czechmovie.com
There is one benefit now – one that can save you a chunk of cash. At the
czechmovie.com, you can buy any film at a 15% discount with the discount code FREE15!
http://czechmovie.com/d/o-princezne-jasnence-a-letajicim-sevci-dvd-1000173/