Congrats on U of C. I too am going to law school although I was rejected at Chicago. Came down to Wash U and Indiana for me and I chose Indiana. Small world, I recognize your name from review.com. Anyways, from my experience with interviews, you won't be handling your travel arrangements and will be taking whatever flight they give you. You probably could request flights, but you really don't want to get too pushy when asking for a job. I'd say that UA and AA are most likely the flights you'll be given for interviews. I'd try and go with AA as I find Advantage to be much better and MRTC is a plus.