UA stopped allowing individuals to use their credit card to buy tickets online for friends (and even family if I recall) earlier this year. There was a big stink about it at the time, including a WSJ article that some FTers brought to WSJ writer Jane Costello's attention. From the NYT article, it would appear that I could buy tickets for anyone on the AA.com site. Obviously don't think it would have made a difference in this case, as the hijackers were extremely well informed about their targets and mission.