Triangle object seen following the Connecticut River

I was driving north on route 142 just by route 10.  Something caught my attention in the sky and no one was behind me, so I decided to get out and look.  I looked up, there was no noise, and saw what looked like 3 white lights flying in a triangle flying from west to east over the Connecticut River.  They made a turn and followed the river south.  Because of the way they turned it seemed like one object.  I watched it go south along the river until I couldn't see it anymore.
My impression is that it was huge, fast, low to the ground and quiet.
The length of each side was about 7 full moons.
Source of report indicates that the date of the sighting is approximate.  PD