Originally Posted by
ft101
It's not definitive. There are ones which are borderline and might be one or the other.
OP. It has been reported that I is Flex but the best way to know is if you have a booking code as you can tell from that. 4th letter from the right. F = Flex Plus / S = Flex / P = Saver / R = Special
+1
to clarify, booking code = fare construction usually at the end of the eticket, not the PNR reference