Can 2 airlines be used on the same award ticket?
 

When I call the TopBonus hotline to book a one-way award ticket ORD-MSY-LHR (which flies on AA metal and then BA with a layover at New Orleans), the agent told me that I can only do it in 2 bookings because it involves different airlines. I called again and got the same answer.

Is it true?

From my experience, in principle it is not allowed, however with exemption regarding flights which are operated by business partners of AB, like EY. I had reward flight last year from SYD to BER via AUH, booked as one flight, where SYD-AUH was on EY and AUH-BER on AB. I wanted to book also TYO-HKG-KUL, but it was not possible, because it involved CX and MH and such combination was not allowed.

I received the information that you can combine AB with one other airline in the same ticket. It was not possible two combine two airlines if AB was not one of them. Information was given last year on the phone.

Unfrotunately yes.

Donegal has already posted the booking rules for TB awards.