Can I combine two separate Avios bookings into a single PNR, or alternatively add a new Avios segment onto an existing Avios booking. Specifically I usually need to book BA flights USA to London before a connecting flight on AA is made available. If I wait until the AA flight is available then the BA flight is typically no longer available. I always end up with separate tickets and all the hassle that entails, obviously trying to avoid this. I know you cannot combine AA and BA flights using a companion voucher but is this possible if not using a companion voucher?