Thanks. No, you have to have a commercial license to fly for hire, so that has to come before the instructor rating. You might be thinking of the Airline Transport Pilot (ATP) rating, which is a whole 'nother ball game.

The commercial rating really doesn't require a lot of flying time, perhaps no more than 15-20 hours beyond what I already have. The most expensive part is the requirement for 10 hours in a "complex" plane - retractable landing gear, constant speed prop, and flaps. I'll have to rent a plane to meet that requirement and they aren't cheap ($108/hr for one that I know about).

As for using the commercial license, I'm not planning on quitting my day job. At 45, I'm too old to seriously consider going for an airline job. Between 1-3 years of heavy flying to build hours on the one side and mandatory retirement at age 60 on the other, it just doesn't seem practical.

I love to teach and I love to fly, so going for an instructor's rating seems a good fit.