Originally Posted by
psychokilla
Hopefully this will explain. I can book eco on both legs on Emirates, and then upgrade one of those (incoming) to business. In order to get business on one leg on Qantas, I would've had to book eco+ on both legs, then upgrade.
I realise now while typing it that this may not be the case, as the only time I've ever tried to upgrade before this was on BA when I was told explicitly that you cannot upgrade by more than 1 class change on a booking, so eco to eco+ only (on 4 class flights), eco+ to bus only, etc etc. I don't actually know if this is the policy with all airlines.
Upgrade how? Do you mean using miles/points?
All frequent flyer programs have different rules relating to upgrading, and generally you can only upgrade on their own flights anyway so your line of questioning is flawed.
Through BAEC as you state you can only upgrade one class.
However through the Qantas FF program you can request an upgrade from Qantas economy to business.
So again, the reason for your question is rather flawed. If you had only Emirates miles you can't upgrade flights on other carriers anyway regardless of the number of cabin classes..