Alien Prequel News says:
Back in March I reported that 'Prometheus' could be partially inspired by Erich von Daniken's hypothesis that mankind was created by aliens, who were seen as gods amongst ancient civilizations. This story was further backed by Ridley Scott himself in June when he announced at the Cine Europe expo that:
"The (space) journey, metaphorically, is about a challenge to the gods. NASA and the Vatican agree that is almost mathematically impossible that we can be where we are today without there being a little help along the way. That's what we're looking at (in the film), at some of Eric von Daniken's ideas of how did we humans come about."