UFO/ UAP over Bozeman Montana. Ship was at least 100 yards width and 20 yards hight hovering for two min and disappearing in a flash

We were driving from Bozeman to the airport in Belgrade with a blue sky and no clouds present when my father said, "Matt what's that? It doesn't look like a plane." That's when I saw it. I looked out the window to my right over the mountains between Sacagowea Peak and Saddle Peak. there was a Huge silver/foggy disk or maybe a cigar shape with a dome on top. I estimate it to be 100 yards in width by 20 yards in height according to the elevation and how close it was to the mountains. It was hovering at the same elevation as Sacaagowea Peak for what we recalled as two minutes. Then suddenly it either disappears or becomes invisible and you could no longer see it. This is not my first sighting but it was my dad's first. I have seen this happen twice in California but this was the biggest ship I've seen yet.