If your young child has an undying love for planes and nearly everything that he owns is plane themed, you might want to consider giving him a special opportunity to go in to an airport or even to an air force base. If he has a birthday coming up you could even consider throwing him a small surprise party that is plane themed and give him the experience of a lifetime to ride in a real plane and meet with real pilots. You may not know it now but maybe your child is destined to be a pilot himself and this experience could be the kick-off that he needs pursue his dreams. It should not be too easy for you to get permission to organize something like this as there are many such experience opportunities for your children. You could throw a party complete with a plane themed cake and plane themed decorations to make it the best experience he has ever has in his life.
Getting special permission
As you might have already guessed, normal people are usually not allowed to go into these places without prior permission but with special permission you might be able to get your son an experience with some of his closest friends to go into the amazing Perth general aviation parking area to witness actual planes, meet with real pilots and possibly even have the experience of riding in a plane himself. You might be able to get him a ride on a close distance plane as a passenger or you might even be able to organize a special ride just for him and his friends but you may need to pay for this experience.
You may need to go to the regional terminal parking area for this. There are many companies that allow special parking permission for people to ride in their planes. There are even passenger experience planed that can be booked for an hour or two.
The key to making it the best party ever is to keeping it a surprise. Alternatively, if the charges are on per person basis, you can even take only your son on the adventure with you and your spouse instead of making it a big birthday party as this could be cheaper for you. Start planning well ahead because getting permission to do certain things could take time and you may need to change your plans from time to time in case there are any road blocks and therefore early planning is absolutely vital.