I am curious also to know the rationale behind the question.

I disagree that a lot business goes to AA/BA. That is simply not true. It depends on the size of the firm, who's travelling, and the destination.

To the best of my knowledge, there is no preferred carrier. Most ibankers I know fly what ever is convenient, based on where they live and where they need to fly out of and when they need to arrive. Because of this, private avaiation (i.e Netjets), gets the vote before any commercial carrier. But these days, it's harder to get away with that. And flying to certain banking centers, (i.e Hong Kong/Singapore) is not economical on private aircraft.

There is no loyalty (really). However, other industries, (i.e Media and Entertainment) tend to be bound to a carrier. A lot of tallent that shuttles between New York and LA fly AA.

One route I see a lot of banking traffic is Singapore Airlines EWR-SIN. That flight is all business class, and is usually 2/3rd's full.

CO's EWR-HKG gets a lot a banking traffic too - depending on the season.