Originally Posted by
David-A
Finally, yes, they may be getting simply different availability access, it is possible.
What was the route?
I've done a fair amount of experimenting, and I feel fairly confident it's the latter, but I might be missing something significant.
Routes and dates too numerous to mention. Here's one I tried the other day: MAD to ORD, 5/25 in C. Bookable on IB.com. Not on BA.com. Not available using AA miles.
As a practical matter, does it make a difference? Usually not. There is no real reason to book using BA miles instead of IB miles. I suppose if you're elite on BA and have access to free change fees (not sure about the program) it might make more sense. But IB change and cancel fees are not that high.
There is, though, one area where it's a bit annoying. You can't book one-way itineraries on IB using IB miles that involve partner metal. So, you might want to book the journey on BA or AA, in order to have it all on one PNR (and, with AA, save some miles) in case of IRROPS.