rolling20,
You will be welcomed, particularly if you have skills related to the RAF or things like DofE, adventurous training or HSW type quals.
The problem you will probably find is that you get sucked in deeper and deeper.
The air cadets is arguably the finest youth organisation in the country but it relies on a vibrant volunteer adult population. You can be a CI, adult NCO or commissioned officer in the RAFVR(T), depending on what you want and if you can cut the mustard.
I joined as a cadet in 1958 and five years later went into the RAF for 31 years and am now back with the air cadets. In February, I was given an extension of uniformed service for twelve months which takes me to Feb 2016 - I shall be 72 then!!
Old Duffer