Indeed, something like 25cm or better is typically shot from airplanes. I don't remember what the physical limit is for image quality given a reasonably sized spy satellite (iirc it's around the 20cm mark), but commercially at least, the high quality imagery is all airplanes. Governments often commission such planes to fly ~yearly at something like 10 cm, as well as commissioning height maps[1], but the very good stuff is not released to the public for privacy reasons. I think the best I've ever seen is 15cm.

The point clouds from those height maps alone, though, I already find to be quite interesting/revealing. You can see the contours of e.g. a tree exactly, even without having any imagery laid onto them: https://snipboard.io/tPsRBo.jpg

[1] For those that can read Dutch, how the Actueel Hoogtebestand Nederland is made: https://www.ahn.nl/ahn-the-making-of