If I'm right, at 16 and by the time he completes his pilot training (circa 5 years from now without university) he won't get much opportunity for FJs in the FAA! SHAR goes out of service before then (only one sqn op now) and all Harrier (RN FJ) opportunities are with the RAF. JSF is due in service in 2012 but govt are already talking about reduced numbers and smaller carriers and the fleet will be split FAA/RAF as Harrier replacement. Therefore, statistically, if he wants the best opportunity to fly FJs, then the RAF must present the best opportunity: Typhoon; Tornado GR4 & F3; Hawk (100 Sqn) & Harrier GR9 will all be in service when your son is ready and available for pilot training, whereas the RN will be downsizing its FJ pilots numbers until it gears up again for JSF. Statistically, if you join the RN now (or after your son's A-levels) to fly before JSF enters service the odds are against you flying FJ but definitely inclined to a career on choppers.
Only my opinion and nothing official intended or implied!
PS. Fair response, A-A, but slightly disingenuous given the lad's desire to fly FJ!