This is what the USAF said. It could very well be a propaganda war. If aliens are real, then they would most likely have bases on Mars, or Gaynemede or Calisto as these offer the most stable of conditions and could hold underground cities or structures.
Why not the moon? We know now that it has water.
Finally!! we know where obama is from!
I vote for alien bases on the Moons of Mars. The way they move seems to indicate they are hollow.