Hiya, im 16 now, but when I was 15 I did work experience at Bristol International Airport. Worked in the tower for a day, customer services and the fire crew.
Also got the chance to stay with Servisair for the afternoon, and the ADM (airport duty manager) gave me a tour of the airport, behind the scenes with the bags etc. Very interesting.
I also hope to become an airline pilot. I applied to a couple of airlines, but they were not taking work experience students at that time.
I learnt a great deal at the airport, and would suggest it if you cannot find a place with an airline.
Good luck