My "business plan" was and still is a 2-3 year one. I moved back home to save on rent, I still pay board and I get no direct financial help from my parents.
I too work in a salaried job and receive time and half for overtime, nothing special there. When I needed an injection of extra cash a few months back I worked in a bar a couple of evenings a week getting paid bar wages too. I'm fortunate in that I enjoy my day job.
I have 3 friends who have done almost exactly the same thing, one is now on the Dash 8, one on the 146 and the other is a FI. All worked, completed a module, worked, completed a module. One of these started at the plan at 18 and she got her first airline position 3 years later, another took less than 3 years starting on the road at 25, and the last was instructing in about the same time and was about 28 when starting out with a mortgage (albeit shared with a partner).
I would not want to pass comment on your individual circumstances or even try to offer advice like "do this, do that", I am just trying to make people aware that it can be done, and by an averaged salary individual from an 18 year old on lowish salary, to a late 20's with a mortgage. However I appreciate everyones circumstances are different and what can work for one, may and by the sounds of it cannot work for another.
Moving on from here, a previous poster has made a good point re credit cards, just jiggle them around, use the free balance transfers etc to boost your capital. Interestingly enough I am led to believe that as long as you don't default on any of these your credit score will be higher when it comes to getting a mortgage.