I would go for Qatar Airways, Royal Brunei Airlines, etc... They don't earn their money by selling tickets... It seems to me, that it isn't that important how full the planes are, their "Scheichs" have the money to do whatever they like... I can't imagine that Doha is such a big market that Qatar Airways will make money with A380... I worked at the Vienna Int'l Airport in july, and everbody there told me that they haven't seen a full QR
-flight once! But the fact is, that they send an A300-600 to VIE
... The route of this flight is also unlogical (at least for me...) Doha-Munich-Vienna-Munich-Doha.... wouldn't Doha-Munich-Vienna-Doha be "the same" and wouldn't this way save them a lot of time? (you remember "time is money"...)
I don't want to start a debate about how much sense it makes to fly the route this way, I just want to tell you the reason for my opinion.
So I think these airlines are the richest, at least their owners...