Help identifying this UFO photo

[Charlie Wiser]

From Center for UFO Studies "On this day in 1987" (Facebook post):

ON THIS DAY IN 1987. May 26, 1987. 9:30–10:15 p.m. More than 100 people around Newtown and Southbury, Connecticut, see a low-flying, silent, circular formation of lights that passes over Interstate 84, causing many cars to pull over for a look and some to lose power. Commercial airline pilot Randy Etting sees the lights as he is driving along I-94[84?]. He pulls off the road and snaps a photo of the formation. He is sure there is a solid object behind the lights.

Several people in the comments report seeing (or hearing about) a similar "UFO" from quite recently to as far back as the 70s, with someone offering the suggestion that it was a

Hughes 500p "quiet" helicopter with circular lights... The light circle suspended below the helicopter could be any width. I saw them use this in 2007.

I can't find any photos of a helicopter carrying a suspended circle of lights and don't know of a reason it might do that.

The case is written up here and here and includes some contradictory info but I'm more interested in the photo and the idea it's something suspended under a helicopter. Details FWIW:

• length of a football field
• semi-circle or boomerang shape
• 200 witnesses
• "The lights were shimmering like distortion from engine heat, but he could hear no sound."
• Some witnesses said it hovered for several minutes.

Can anyone illuminate the helicopter idea, or offer suggestions for what the photo shows?