Phoenix Lights? Seen from the Air.

On approach to the Phoenix area from the northeast aboard 57-1465,  a crew member alerted me to ATC radio traffic concerning UFO activity.  Prior to this, and for several minutes, I noticed a pattern of whitish-yellow lights in line formation, with slight variations in altitudes, in the relative proximity of South Mountain.  They were visible for at least 40NM.
Prior to hearing the radio traffic, I was under the impression I was seeing very bright lights coming from atop the mountain, as I knew there were horseback riding trails in the area.  I can account for seeing five lights as I remember they formed a shallow W-pattern similar to the form of the Chair of Cassiopeia, however this was in the southern sky and appeared below our altitude.
ATC radio inquired if we saw the lights, which we acknowledged, and it was overheard that the lights were visible from other aircraft and from the ground.
We turned to the north for an approach into Luke AFB and upon completion of that approach, turning toward the south, the lights were no longer visible.
In later years, I was informed they were probably flares in the MOA to the south of Phoenix, however, I am familiar with air-dropped illumination flares, and although there are similar characteristics, these did not appear the same.
This information is extracted from my log-book.
Reported by a military navigator.  PD