Originally Posted by
TheMoose
I've been told that things catered for one flight are only good for that flight and no other. It all gets offloaded at the destination and re-catered with new food/drink.
Whether or not that's true is up for debate as I've been told a lot of things in my time...

Operationally, that makes sense - it's probably far more efficient and far less error-prone to just take everything off and then load on the full compliment than try and replace just what was used in the previous flight.
But, I would expect that once off the plane, any unopened items would then be used for a different flight later. Can't imagine they just throw out bottles of wine.
I think the real question here is whether airline wine counts as a gift.