Can models still use any time abilities, like battle plans, when they are knocked down? The text from previous editions where knocked down immediately ends your activation is no longer in the rules, and as far as I can see, knocked down does not limit the use of any time abilities. It specifically calls out attacks, spells, feats, and special actions, but that’s it. So if a model gets knocked down during their activation, can they still use any time abilities?
You have quoted all of the relevant portions of Knockdown. Knockdown lists all of the activities that are explicitly prohibited.
Because it does not list “Use battle plans” and other such rules, you are allowed to use battle plans while knocked down.
(In previous editions, the portion about “if you are knocked down during your activation” was only ever connected to throws and slams, and was added to stop players from throwing their own models to extend movement/charge ranges. Because models generally can only attack enemy models and generally may not attack friendly models in MK IV, those parts of the rules could be removed.)
You’re thinking of “if you are knocked down in the same turn and you are steady” . ( I remember the flying Drakhun)
I couldn’t find anything about your activation immediately ending like how it used to be so you could assume that you can in fact use battle plans.