Where can I buy ?

Travel Info
Air Force items (shirts, jackets, caps, etc). Does not matter Air Force of which country. Thank You.

Travel Tips

Other than shops, you can find the suppliers of these items at lorong haji taib. You can say u are buying for samples. They have the garments, batons, beret, badges, shoes, epaulete, everything you might need.
Others

Join the Airforce and you won't have to buy them, they'll be provided free.
Otherwise Victoria Park Market will have this paraphenalia at a few stalls for a reasonable price.
Driver T
You can get them at ground floor PuduRaya bus terminal. They have loads of them catered for Army personnels, Airforce, etc. and wannabes. They're also available at Pertama Complex...

A wide range/variety to choose from. If you're really enthusiastic, make a trip to Aranyaprathet market at the border of Cambodia and Thailand. You'll get a lot more options to choose from. Some are genuine items left behind/sold by foreign troops.