Is there any data (reports, statistics, etc.) on the percentage of first and business-class airline tickets that are purchased out-of-pocket by the passenger?
Meaning, NOT received due to a loyalty-program upgrade from Economy, NOR purchased by the passenger's employer/business arrangement/etc.
Articles like these make it clear that for medium- to long-haul flights, First and Business class tickets can routinely cost $10,000 or more. I can't imagine many people actually pay the full sticker price out of their own pockets.