Good question. Many years ago we didn't have as many airplanes so the CF-XXX configuration had enough combinations. Eventually they did run out combinations so they added "G" letter and changed the format from CF- to C-f and C-G as in C-GPSU. For the Ultra-Lite category, Canada uses the C-I designation. I hope this answers any questions. If you do see a Canadian plane today with a CF- designation you know the paint job is more than 30 years old.

Harry Wiebe
Winnipeg
C-GPSU