I agree that AF on LHR-LAX will have to focus more on the US-based traveler and this is where Delta comes in. Remember that this won't be just a regular codeshare with DL selling some seats on the AF flight but rather a 50-50 JV. Hence, DL has just as large an interest as AF in marketing and filling this flight. Of all the SkyTeam carriers, DL probably has the largest presence at LAX (summer peak of close to 100 flights a day with service to almost 50 cities (around 35 domestic)). And DL still has a very decent FF base in the LA area.

As for LAX connections, DL has boosted its LAX flights quite a bit recently, so there can be feed from places (only listing those without too much backtracking) like HNL, OGG, SFO, SAN, SJC, OAK, RNO, SMF, or even AF's own PPT-LAX. In addition, DL has codeshares out of LAX on American Eagle to FAT, SBA, etc., that can be marketed straight-through easily on a DL-coded ticket.

On the LHR side, don't forget to look at this from the overall SkyTeam perspective; from LHR, there will be 9 daily flights from LHR to the U.S. by all ST carriers by next summer to at least 7 US cities (JFK, ATL, LAX, SEA, MSP, DTW, IAH) and perhaps EWR. And AF will pretty much have their code on all of them....I don't think that's a bad start for AF at all...Contrast this with BA out of Paris (for its proposed 757 service to JFK): BA will be wholly dependent on the JFK side to generate traffic as its once daily offering from the French side will be miserably inadequate - and it won't even be codesharing on AA's CDG-USA flights to give it more heft in the Paris-USA transatlantic market...