This is pretty simple, really:
The Inca Nazca lines in Peru
Plus the Chariots of the Gods
Equals ancient Incas in Norway.
So, after a long trip to Peru, these two aliens hit the O-
club after landing. They get all liquored up and offer to take the bartender and his family on a joyride. The bartender, realizing the no Inca has ever been allowed within 100 yards of a ship thinks this is his chance at greatness and accepts immediately.
They all load up and go flying around earth. They are near Norway when the aliens start to sober up and realize they have violated just about every rule in the Alien Space Pilot Flight Operations Manual. Realizing that if they dump the Incas in Norway no one will ever know, they land and boot the poor Incas out into a foreign land.
The Incas can't speak Norsk, so the secret is safe. It turns out the Incas get sick from lutefisk and die though.
The Vikings, realizing that these Incas simply came out of the sky, figure they must be divine, so they bury them in church and worship them.
Any other questions?