Originally Posted by
majfly
Thanks for the clarification, I was thrown off by the 4 letter code. I actually just checked on the ITA tool and they spit out a 1 letter class, which matches the first letter.
You're confusing the fare basis (4 letter code, can sometimes be more) with the booking class (1 letter code).
As Kiwi Flyer says above, the first letter of the fare basis is usually the booking class, but not always.