Originally Posted by sftrvlr
Gosh! How long did it take you to check in?
Actually, United will interline your baggage to ANY airline they have an interline baggage agreement with. If it's not in the same record, you'll probably need to show an e-ticket receipt, or a paper ticket. When you arrive at your connecting point, your onward carrier will ask you if you checked a bag, and (should) ask for your bag check receipt(s). It normally works smoothly.
Correct. This shouldn't be a problem-- I'm guessing that UA has an interline baggage agreement with Aeroflot, in which case no issues. The only two airlines (outside of some LCCs) that are becoming difficult about this are BMI which will not interline to any carrier on a separate ticket (including themselves!) and BA, which will only interline to a OneWorld airline on a separate ticket.