You don't need A levels to fly aeroplanes.
But that said, I STRONGLY recommend that you do not use clearing to get onto a course unless you have solid grades in the relevant subjects (if it is a scientific / technical field. If you are going to do some bull**** degree then it doesn't matter).
Case in point, I bombed my Maths A level (Grade D) although got a pair of As in Physics and Chemistry (this was before A*), with merit on the special paper. I'd been hoping to do Aero Eng and had a couple of conditional offers but with a D in Maths they turned me down. I then went through clearing and got a place on an Electrical Engineering course at Leicester. Huge mistake. I couldn't handle the Maths at all.
As far as job applications go; (aviation or otherwise) it depends on the HR department and what they want in the way of "chopping the applicants down to manageable numbers". You should also bear in mind that sometimes doing something and screwing it up can cast doubt on your commitment and suitability for training in general. You might want to invest some time into thinking about how to cast the performance in a positive light at interview.