Not just slow momentum, all but kill it, though vertical height will be reached as normal (for a running forward jump, though, you'll still travel some distance and will need an air combo to stop dead - but those are a lot harder to do accidentally, and if you do, you'll probably want to just double-jump back the way you came).
The air control is very handy if you're in a situation like this one, where a forward jump will be instant suicide into a pit:
And if you're really in a pinch, an air combo will instantly kill a jump's forward motion and vertical climb (even a running forward jump). This is also a handy offensive property of the AC - you can perform rapid successive ones by jumping, executing the AC immediately, landing and repeating. Very handy if you're underneath a boss!
In Strider 1 news... good grief. Where do people even get the idea that the PS1 port of Strider is "based on the Mega Drive version" ? I've seen it on this forum and a few other places over the years, guess I shouldn't be surprised
Youtube brings the goods too. Fortunately Bloodreign contributed some much-needed sense.
I guess casual fans remember the excellent MD port as even better than it was, closing the already relatively small gap between it and the PCB, then proceed to trash the PS1 port for... being based on the PCB.