I think this was from the 1980s, a series of fat books. There is a leader called the Axe or similar, a woman who plants trees, and lots of military stuff. Also some immortals who interfere and torment people, they can fly, and turn out to be aliens. At the end people enter the hidden spacecraft and reclaim their heritage. Maybe Star something? I thought the author was Colleen McCullough but can't find these books in her list of works.