Your best bet is give your AAdvantage number when you check-in for your BA legs of the trip because sometimes the computer can't handle or will "confuse" your CO and AA numbers.

I have taken 2 tickets where I flew CO EWR-FRA and was LH from FRA to my destination. It was a CO ticket and I got my OP mileage no prob for the EWR-FRA leg, when I checked in at FRA for the LH segment and got my boarding pass, I would ask the agents to add my United number. My miles always posted on both CO and UA timely.

So, giving your AA number to BA at checkin I am sure won't be a problem because if you do it before it might kick out your CO number.

- HobokenFlyer

[This message has been edited by HobokenFlyer (edited 01-10-2002).]