What is a hypernym for the ascending and descending legs of a flight?
Since a hyperonym can be a word or phrase, I'd go for a non-cruise airborne segment. Or N-CAS, as it'll be known from this moment in history.

The ICAO Common Taxonomy Team (pdf) doesn't have a term for it though.

From that document you can call 4, 5, and 6 (from your diagram) just en-route. And I don't see harm in expanding that term to include 3 and 7 as well (for the purposes of the question).

Also during cruise, some planes continue to climb in steps, it's called a step-climb. In that case you end up with multiple climb and cruise phases.

Which makes me think of stepping.

Officially there's no answer to your question, "en-route" fits in fine and is official, and "stepping" (up or down) would exclude the cruise as you requested, it works from a technical (albeit very broad) standpoint. But it can't be used officially or otherwise if you ask me.