In '63 United would have had DC-6s, DC-7s, DC-8s, 720s, CV
-340s, Caravelles, and Viscounts.
seems that it would have been more or less a DC-6 city at that time. But I can imagine that some of the trans-con milk runs would see a DC-8 or 720 flying between Salt Lake and Boise.
Stop drop and roll will not save you in hell. --- seen on a church marque in rural Virginia