I remember that in earlier backer builds there was fuel mechanic: PP airplanes had to refuel limiting their exploration range. In order to explore further they had to build fuel depos or find friendly heavens.
This mechnic were cut a while ago, and it doesn’t seem like it will reappear.
Is there any other mechanic in its place encouraging steady expansion and exploration? Can we now pretty much go whenever we want to from the get go? Personally, I liked the mechanic, at least from the conceptual point of view as never had a chance to try it myself. Building your own “railroad” through the desolated land seemed appealing to me, possible making some of NPC heavens of personal importance to us. In addition it might have made for an interesting aspect of strategy, defending our travel paths from alien influence.