z114d
Without first time passes in your GCSEs, (and indeed your driving test) you have very little chance of being sponsored by an airline. Sorry to be so blunt. Assuming no sponsorship, you do not need the GCSEs or A-levels to become a pilot, so I would not bother studying for them now.
In my school, if you were in the top Maths set, you did a lower paper GCSE at the end of the first year of GCSE study. Even if you got 100% in these lower papers, the best grade you could get was a grade C. However, you had to obtain that grade C pass, or you would drop a set the following year and never have a shot at doing the harder papers and obtaining a grade A or B at the end of the full two years. Stupid policy, but that is what they made you do.
I was a sponsored pilot. At the time of my sponsorship application, I had 7As and 2Bs at GCSE level (plus the C obtained above), 2As 1B and 2C's at A-Level, a 1st Class Physics degree from the top university in the country for Physics, and I was half was through a Physics PhD at that same university. The company still quibbled over my C grade in Maths, and the fact that I had taken the exam twice in order to obtain the A. They were not at all happy about that, even with all of my far higher qualifications; although granted, it was those higher qualifications which prevented my application from being thrown in the dustbin without interview. They only stopped complaining when I explained that I would never have been able to get the GCSE A without sitting the first exam, and then I would never have been able to take A-Level, and then I would never have been able to take the Physics degree, and then I would never have been doing a PhD.
My point is, unless you have very good reasons for not having the GCSE passes already, your chances of sponsorship are minimal.
Good luck with your goal to become a professional pilot, but I think you need to rule out sponsorship.