This is, I suppose, a follow-up to my recent comments about Concorde. Once upon a time, so the story goes, it was possible to send a man to the Moon, using a Saturn V rocket. But you don't get rockets like that any more, as xkcd shows us by reference to horses and Pegasus (go here to see it full size).
See also here: "If we could land a man on the moon, why can't we -" "- land a man on the moon?" (It's often worth hovering your cursor over the cartoon with xkcd, certainly worth it at the latter link.)