Airfare.com has very good fares, about $200 less than aircanada.com for a flight that I'm about to book.

I credit all mileage to United. Wondering how to find what's the booking class for the ticket booked at airfare.com, since I don't want to get dinged for booking in a class as I read on United FAQ - "Booking Classes K N G P E T do not earn miles on flights within North America."

Thanks in advance!