Haven't flown domestic for awhile now, but when I did, most CAs would always offer a first class seat if it was open. If they didn't, I would prompt them.

Irish Tiger, sorry your experience was so bad on us. Perhaps you should stick to Delta so that they can always cater to your desires while bumming a free ride. In the meantime, if you ever j/s on one of my flights, you can be sure I will do everything I can (within my F/O capabilities) to get you your first class seat.

73