Originally Posted by
goldfishman
Why not just ticket on UA and credit miles to CO?
If I can ticket on CO, then I can likely fly only the EAU-ORD leg on UA metal. If I ticket on United, I'll likely be flying the entire itinerary on UA metal.
If I'm going to fly the whole itinerary on UA metal, then there are advantages to being a UA elite instead of a CO elite - higher upgrade priority, better IRROPS help, use of CR-1's, blah blah.
In other words, if I'm going to pretty much always be flying UA, why bother with CO at all?