A few things,
Evidence that there was at least SOME connection between the two cultures, besides their propensity for pyramids.
In mummies in Egypt, there has been numerous traces of Cocaine found, along with tobacco and Cacao (yes, chocolate) in the bindings and bandages. NONE of these are found in the old world, and at the time (we thought) were only found in the america's. How did it get there. I FIRMLY believe that the phoneceins (sp?) had far greater trade routes, and could/were trading with the New World at a time when most of science believes that Britain was as far as they got.
The Nazca lines. Forget aliens. I have read/seen evidence that the Nazca were using balloons (of the hot air variety, lol) to get them up high enough to see/sketch the shapes and drawings. I even watxhed them make one of said balloons on the History channal using only materials that they had (mostly a very strong, lightweight fabric they made) to do it, and they found it was entirely doable.
Back to the mesoamericans and the folks in Egypt. I think it is very likely thatthey had contact with each other at that time (and not via Atlantis or aliens, or whatnot). Their cultures just seem to have too many similarities.
hehe, cocaine mummy's! Middle Kingdom drug dealers. I love it!