I have booked a flight through United from Boston to Phoenix for March 19-26. Both of my flights say "Operated by US Air". I was just curious so I checked US Air's flight schedule and my exact flight is also listed on their website with different flight numbers. I thought I read somewhere before that sometimes airlines share flights to help fill the planes better. My question is do I go to the United terminals at Logan and Phoenix airports or do I go to the US Air terminal? Thanks.