I signed 2 lines under my AAdvantage number. When I tried for the third, MCI said only one 25K bonus per airline account, but since they had signed me up twice, they would give me the full 50K. To date, I have received 30K.For the other lines ( including cellular) I went with one Delta, one Continental, and one for my 5 year old daughter's AAdvantage account. If you call MCI and don;t like what you hear, call back and try again. You will get a different answer every time !!!