During the bankruptcy they had to open their books. (computer records really) Envoy consistently earns them around $100M a year. The 10 year low was around $75M and the high was around $114M, IIRC.

Regardless if AA does the flight, or AE does the flight, the profit ends up back at AAG. You better believe they know exactly where the money comes from, or goes to. In many of the years AA ran at a loss, while AE ran at an - on paper - profit. The combined from all revenue streams was still negative. At the time of the bankruptcy, AA had a negative cash flow, and AE had a $93M profit that year.