Booked UA+US Air flights through UA, which ff account should I use?
 

I am flying SFO - NYC, and made a booking via the united website. SFO-NYC is a UA flight, while the return is two US Airways flights. I am a silver BAEC member, but don't have any miles on United yet.

Should I let the UA flight's miles go to my MileagePlus accoutn, and send the USAir miles to my BAEC account, or should i use my MileagePlus account for the whole trip? Since the USAir flight is booked through United, where will I get more miles - MileagePlus or BAEC?

US Air operated flights will earn nothing if credited to MP (no RDMs, no PQMs, no PQDs).

Use MP on the outbound.
Use BA on the inbound.
You have to use the US PNR to do that after you fly out.

Thanks! I should wait till I complete the trip, and then add the US Air miles first, followed by the UA miles ? I ask because the UA confirmation number has both outbound and inbound flights linked to it, while the converted US confirmation number only has the inbound flight linked to it. I'm worried that if I add my United MP number while checking in, that info will go into records for the round trip and I won't be able to claim BAEC points for the return US Air flight.

Thoughts?

You booked through UA, so UA is the owner. Anything you give to UA may go to US. Nothing you give to US should go back to UA.

This is the sequencing that should work:

1. Enter the UA number at the UA site.
2. Then, enter the BA number at the US site.

Given you don't have any status on either airline and nothing to lose by not having a FF account attached, your strategy sounds good and minimizes problems.

I am a Silver on BAEC, and Premier Gold on UA (via their status match).

The advice above makes sense then.

Put your UA number in on the UA site/UA PNR and the BAEC number on the AA site/AA PNR.