I plan to fly to the States ex AMS for cost reasons. Hop over to AMS on BA in the morning same day. But I'm conflicted over choosing 2-1/2 hours or 4 hours layover in AMS. Anyone know if I will be able to get a boarding pass from AA without exiting through security. Either on-line or at a transfer desk airside? I have the concern that if a passport check is needed for BP and if that has to be done at check in counters and if AMS is having an off-day on security (it happens) and assuming BA is late again, then the 2-1/2 hours is too tight.
It is not a through ticket from LHR (which would defeat the pricing attraction) so it's down to me if I miss the AA flight.

Thanks