Which airline and FF program?
 

I will be flying to London on probably either DL or US. I can express a preference for which airline but am not guaranteed a specific airline. I will join the FF program of the airline I end up being ticketed on. Would I be better off with DL or US/UA? Will they match AA plat status. Which is better for upgrades? Would UA be the best since I enjoy asian travel? What about the bankruptcy situation with US/UA? Which offers a better coach product since I will not have a way to upgrade this trip? I am DFW based.

I would choose DL
 

You run a heckuva risk if you put miles on US. tls

I would put the miles towards UA if I flew US but I am not sure if that is much better.

If you have AA plat status, why not go to london on AA?

Because I am not the one buying the ticket and AA is not one of the options I was given. I would go on BA or AA if I could.