No, I did not start a company. I’m certain because (a) I do not yet have the “Entrepreneurial Spirit” achievement; and (b) my Career mode home shows “0” at the bottom in the “Company” choice box.
On the other hand, I did browse several company types, and was looking at their prices and aircraft, and I think I clicked one one or two to see what sort of details popped up. I wonder if I accidentally bought the G2 helicopter, but did not fully purchase the FlightSeeing company? When I start up the game later today, I’ll try to find where the list of aircraft I own is. If I own a helicopter, that would explain what happened.