"America has seen a spate of alleged UFO sightings in recent weeks and months. Eyewitnesses in Arizona, Illinois, Arkansas, North Carolina, and other states have reported seeing mysterious lights and objects in the sky.
Among the sightings:
In November 2006, United Airlines employees reported seeing a large, dark, “saucer-shaped” craft over a terminal at Chicago’s O’Hare airport. It hovered for a while, then suddenly rose and shot up into the sky.
In January 2007, multiple eyewitnesses reported seeing a formation of mysterious bright lights in the sky over western Arkansas, moving too slowly to be aircraft.
Similar lights were reported this week over Phoenix.
Could such sightings be alien spacecraft? Of course it’s possible; many things are possible. The question is not what is possible but what is probable—what evidence and logic suggest. Before jumping to conclusions about ETs in spacecraft, we must look at the most likely explanations. "
LiveScience.com - The Reality of Recent UFO Sightings: