Skippy,
I got the info from Antony Preston's book "Royal Navy of the 20th century" I would argue the point about single seater Aircraft as the reason for the 15% dark blue element was for Observers. I'd also say in those 3 years that much more air capable ships came into commission however I will check.
The FOURTH Air Force was going to be the Noggies but having Just seen their wedsite it appears that they are reorganising into a single defence force.
10/10 for spotting the mistake
Al