Without wishing to be cynical (me cynical???) I don't see a problem with any members of the Royal Family being allowed to fly in the RAF or the Navy.
Nowadays, none of them is likely to see front line action, for reasons of press hounding and the resulting placing of their fellow soldiers in additional danger.
I am not against the royal family but IMHO it does these people a lot of good to learn some discipline.
As regards colour vision, it has been
proven (to anybody willing to listen objectively) that CV has barely any relevance to flying. Like much aviation stuff, it's a hangover from WW1 when pilots were real men with hairy chests and anybody remotely considering following in their esteemed footsteps had to be as good. Things have gone downhill ever since open cockpits went out of fashion
