Elon Musk and Jeff Bezos are both trying to make a business of space. I have said many times: It takes the same amount of energy to fly a pound to Australia from Los Angeles as it does to put that pound in orbit; airlines operate at a small multiple of fuel costs; but airlines do not push the airplane into the sea after its first flight. Both Musk and Bezos have flyable used space ships.

Jerry Pournelle