Phoenix lights

The Phoenix lights were lights seen in the sky over Phoenix, Arizona, on the night of March 13, 1997. They are widely promoted by ufologists as evidence of alien spacecraft, despite confirmation by the US Air Force that a squadron of A10 Warthog aircraft was dropping flares over the area that night as part of a training exercise.

Sightings
Many Arizonans reported sighting mysterious lights in the sky on the evening of March 13, 1997. Some described seeing a V-shaped formation; others described observing hovering lights, moving groups of lights, or lights appearing to fade after they passed their position. Initially, Arizona military bases said they had nothing in the air that night. Months later, they checked logs of visiting aircraft and confirmed that the Maryland Air National Guard had taken part in a formation exercise that night where aircraft peeled off one or two at a time to drop flares.

All I'm saying is, yes, we had aircraft flying in that area doing night illuminations. These guys were flying it. They were there. We can prove it. Whether people want to believe it was the mysterious lights, it's up to them.

Investigating UFOlogists gave no small amount of credibility to wildly varying descriptions given by witnesses: huge boomerang-shaped craft, luminous globes, spinning disco balls, etc. They generally failed to account for normal human errors in estimating speed and distance or for other visual misperceptions of two separate events: the formation of military aircraft cruising over the state at high altitudes and flares dropped by those aircraft.

Governor's response
A press conference (featuring many lame jokes and an aide appearing on stage dressed in an alien costume) was promptly held by Arizona Governor Fife Symington. In 2007, Symington further developed his comedy stylings by publicly rejecting the Air Force explanation and espousing the view that the lights would remain "a great mystery" that "couldn't have been flares because it was too symmetrical." By 2008, Symington was appearing on the History Channel's UFO Hunters and Larry King Live, promoting the serious business of ufology to the public.

NWO conspiracy
According to New World Order conspiracy cranks, the military at Fort Huachuca south of Tucson, Arizona, dropped flares to confuse people and hide evidence of a "psychological warfare test" that created indistinct shapes in the night sky via some sort of holographic projection device. Because the NWO wants people to be confused. And looking at lights in the sky.

Pro-alien arguments
But they couldn't have been flares; flares don't act like that! Proponents of the UFO hypothesis sometimes show photos of the V formation made by the aircraft and "prove" that they couldn't have been flares, confusing the earlier appearance of the aircraft with the flares that appeared later.

Why aliens might now be avoiding Phoenix

 * Trigger-happy sheriff departments