Originally Posted by Mwenenzi

Upgrades are normally only on the airline of you ffp.
But AA-BA-IB have a cross airline upgrade system, but with heavy t&c's so little use for most people.
And upgrades are hard to get.

For short flights time & cost benefits will be better than earning a few ff miles.

Having 3 OW ffp's QR, AY & BA is not very efficient. It may have been possible to credit flights to 1 ffp
The airline you fly and the airline ffp you credit flights to does not need to be the same.

QR points have a hard expiry (3 ~ 3.5 years) so would be considering using those :- expiry thread Miles/Points that Do and Don't Expire. Click to open the wiki.