There have been a lot of comments so far about the actual qualifications you could study for and one thing not mentioned so far is their transferability (is that a real word?). A levels are a universally recognised qualification that can open a lot of doors to courses, jobs etc. If you take the time to study and gain a JAA licence and a few years down the line decide to change tack, there are not that many choices - especially without other qualifications to add in. The licence has no direct relationship to, say a degree or HND or whatever, and most people outside of the industry even know it exists.
It is a lot of work to get a licence, which ever way you choose to do it and , as with all industries, there are no guarantees of a job at the end, but with licenced engineers becoming more sought after I would think you would find a job anywhere, if you were prepared to look for one - granted it may not be a first choice one, but it's an ever changing area to work in.
You could also look into doing a course such as the ones run by Brunell in Bristol.
I did an apprenticeship in the RAF and after leaving studied for my CAA licences myself. Took me nearly 3 years to get the first one - mainly due to laziness. If you really want to gat into this job, I would reccomend getting licenced as soon as possible for job security as well as a wider choice of jobs. Having said that, there are jobs for unlicenced fitters, who can earn a very good wage as contractors, but you would need a trade apprenticeship behind you and be prepared for a varied work schedule.
If this is the job you want to do, then go for it. I wouldn't try and put anyone off. Best of luck
