Maybe the Colorado Rocky Mountains are different, but they don’t have plane noise like that outside of the corridor the interstate follows, which the planes also mostly follow.
It definitely looks like there are some larger plane traffic gaps out that way compared to here in the midwest, but if you look at a live map (https://www.flightradar24.com/41.21,-101.72/6 ) they are still flying over even the remote areas pretty frequently unfortunately.