Hello. I have never done this before, but due to timing, I had to book a return flight with both US Air and United. Here are my flight details: FLIGHT # 486 Operated by US Airways DEPART 4:15 PM SAN ARRIVE 6:32 PM PHX FLIGHT # 486 Operated by US Airways (no plane change) DEPART 7:40 PM PHX ARRIVE 12:02 AM ORD FLIGHT # 3516 Operated by Shuttle America dba United Express DEPART 10:10 AM ORD ARRIVE 12:38 PM PIT When I looked on USAir.com, my United flyer number was listed, but not my US Air. Even though when I booked, Orbitz for Business transmitted both US Air and United number over, and I have 2 seperate confirmation numbers. So I called US Air to have it updated, but the representative advised that I could only get credit for one of the flights. Either the ORD to PIT leg on United, or the SAN-PHX-ORD leg on US Air. I opted for the US Air as Ill get more miles, but that sounded strange to me. She did add my US Air number on the reservation. I checked on United, and it still has my flight detials with the ORD to PIT leg crediting to my United account. Is this correct, or will I get credit for both legs and both frequent flyer accounts. Second question... Im spending the night in Chicago, arriving from US Air and departing the next day on United. Will my checked bag come up? The represtentive advised it probably will not and it will most likely transfer to United. Anyone have this situation before? I just need to know what to pack in my carry on vs. check and I really dont want to be waiting at baggage claim at midnight for a bag that wont be coming. Thanks everyone.