As I posted elsewhere I am planning a trip to LAS in March and pretty much decided to route LHR-MIA-LAS-MIA-LHR to get the 600 points I need to keep Silver. While LGW-TPA-MIA-LAS-MIA-TPA-LGW would be much cheaper and earn more TPs the timings would result in an overnight in either TPA or MIA each way.

I have priced LHR-MIA-LHR on ba.com and MIA-LAS-MIA aa.com but thought I would try booking it straight through on one site.

ba.com was a nighmare. Selecting the "multi-city" option I entered LHR-MIA, MIA-LAS, LAS-MIA, MIA-LHR. ba.com decided to route me as follows:-

LHR-MIA
MIA-LHR//LGW-DFW-LAS
LAS-DFW-LGW//LHR



Entering the same itinerary on aa.com brought about far more sensible routings but only gave the option of AA flights on the LHR-MIA legs. Obviously these are no use as the key for me is TP earning flights. Does aa.com ever offer BA flights on routes where they compete?