Do you want to start with historical models and ten try to 40K-fy them, or do you want to start with SF models and add winged decorations to them?
Back in the day, GW used to manufacture fantasy models inspired by the winged hussars in their Kislev range – these models were called Winged Lancers and Gryphon Legion, but might take some searching for in the second hand market.
The Assault Group manufactures historical Polish figures including hussars, but these will likely look a bit on the small side if placed next to GW models:
link
However, the hussar wings are also availailable on their own:
link
Also Wargames Foundry makes winged hussars, same reservations apply (and the wings might not be available separately, though I have not checked thoroughly):
link
If I am not mistaken, GW also made Dark Angel Ravenwing bikers (Dark Vengeance set) that came with feathered wings – if you can find those separately from somewhere they could be handy.