Orange lights in the sky with smooth but random movement that joined in formation to form a triangle, then accelerated away from us.

I work medevac and fly on a pilatus PC-12. We were en route from Salt Lake City UT to Idaho Falls ID. We started tracking a series of lights (3-4) to the North East of our position around the time we hit the Idaho/Utah border. One of the lights appeared to have a parallel flight trajectory to the east of us off our right wing. It was several miles out. We radioed in to the SLC ATC and inquired if there was any traffic in our vicinity. We were instructed that there was no traffic. No other aircraft responded on the radio about being in the area. There was nothing on radar or a transponder signal. Eventually the light disappeared, but reappeared at a higher altitude, and there was 3-4 lights moving at a speed not consistent with any aircraft that we would be familiar with moving in random but smooth patterns. We were at 20k feet. These lights would fade in and out and all have different vectors. Eventually they all met up, formed a triangle formation with 3 points of light (one on each corner) and one faint light in the middle and it moved up and vanished. We landed at Idaho Falls and still noticed 1-2 lights at a time coming down (possibly through the atmosphere) flying in random patterns at different points in the sky, then vanishing. This whole phenomenon lasted about 45 minutes. We are pretty used to seeing meteor showers at night since we fly a lot of night missions, but none of these lights had the characteristics of meteors based on movement. It was very awesome to see.