I propose another root cause for the difference in the belief in extraterrestrial intelligence and specifically alien visitations. There is likely a better understanding of fundamental principles of math & science on the right as a lot of your lefties were educated in liberal arts colleges where math stops at Algebra II and Intro to Geometry.
As a conservative with an engineering background I think I have a better grasp of the technical problems associated with long-duration space flights. While I allow for the possibility of a great leap in scientific insight that might invalidate my opinion, I think that it's exceedingly unlikely that UFO's represent alien spacecraft visiting our planet. You're average Lefty believes that the oil industry has been hiding technology (at Area 51, no doubt) about an automobile engine that will get 100 mpg on tap water. It is this ignorance that has allowed our energy policies to become badly distorted.
I'd not even give them that much credit.
Figure that these are people who tout totally impractical boondoggles such as solar and wind power, with no understanding at all of how electricity is generated, how it gets to their house, or what happens when they turn something on. "The three prong thingie needs to match up with the holes in the wall" is the extent of their understanding.
For instance, I've been looking forward to what California's electric car mandate will do to their already overtaxed-and-prone-to-brownouts grid. Especially, when they're not allowed to add stable sources of power (think coal, gas, nuke...."wind" doesn't count) to the grid to help.