Study hard now and get as high a grade as you can in each of your school exams. Go to the best possible university you can get into and do something numerical - based on your A-levels, economics would do nicely. Having a relevant degree will open doors to you that will in practice remain firmly closed to someone without a degree - the minimum requirement on a job spec might ask only for A-Levels but if 90% of job applicants have a degree those school-leavers had better have an exceptionally strong CV even to get an interview.
I would caution possibly against doing a degree purely on aviation in case you decide in future years to change industry or career; aviation is a cyclical business and when there is a recession airlines cut thousands of staff including network planners - you need to have the ability to work in other industries just in case there's a big terrorist incident like 9/11 and through no fault of your own you get laid off.
Enjoy your 3 years at university and make sure you get a Upper 2nd or First grade at the end of your degree. I notice you are not doing A-Level maths - it will stand you in very good stead if at university you can get your maths and statistics to at least A-level and ideally higher. Learn a mainstream programming language well (C# or Java are good candidates) so you will have the ability to analyse raw sales / marketing / revenue data from first principles - big data mining and analysis will be an increasingly important theme.
In your 2nd year at university, apply to airlines for an intern role in network planning or maybe revenue management or a finance-based role. This means you spend maybe 2 months working at head offce for the airline in a very junior version of the role you'd like to do - they pay you and may give you a project to work on, you get to meet senior people and they will remember you instead of just treating you as one of a crowd; it becomes essentially an extended interview and if management like you the company will offer you a job for when you finish university.
In your 3rd year at university, if you haven't already been offered a job, apply to the graduate scheme of as many airlines as possible - you will learn a lot more in the first year on the graduate scheme of a large airline that you will on a small airline.
Network planning for an airline is a somewhat niche role and careers advice on how to enter it is pretty rare. Ask a careers adviser about 'operational research' and you may find some more informative career guidance
Obvious though it may seem, remember also that the roles of pilot and head-office staff are very different.
Last edited by davidjohnson6; 29th Oct 2016 at 23:52.