After Raven developed the first modern hot air balloon in 1960 – 1961, there was no pilots license requirements by the FAA. 

About 1962 or 1963, Raven started to work with the FAA regarding the Hot Air Balloon license category.  About 1964 the FAA introduced this category, but there were no experience, knowledge requirements to get it, all you had to do was to apply.  Therefore, there were a number of people who had never had any training in a balloon that now had a FAA license to fly one.

Later the license requirements changed to require a minimum of 8 hours of balloon flight experience, and passing both a written and a flight test.  There was no Private license, only a commercial license so now armed with a minimum of 8 hours you were now a commercial hot air balloon pilot.

Starting the Fall of 1974, the FAA was changing the license requirements to what they are today with both the Private and Commercial license.  Therefore there was a rush of balloon students to hurry up and get their license prior to this rule change, myself included.