So if at the moment when the offense player jumps it is clear that they will collide with the expected position of a moving defender, it is a foul by the offense (see rule 12.7). If the defender and offense player are both moving to the same spot at the same time, that would be an offsetting foul (see rule 17.9).
Also worth noting the official annotation to rule 17.8.1: If the offense commits a foul after establishing possession in the air, but the foul was caused by actions not related to the process of making the catch (eg while attempting to intentionally land in the end zone), this should be treated as an indirect foul.
Hope that helps.