Dude your layout is amazing.. i too am in the process of designing and making tarmac to display my collection. I did some trials but the results were not what I desired so as soon as I can I will try to post some new pics..
HJMEMON and RAIHANS - thanks for your comments. I didn't try simulating any airport - I'm still trying to figure out how I want to display my collection, which seems to be growing all the time. This is a small and manageable 33" x 22" diorama which makes it more fun to take pictures of models
PK777 - Thanks - the layout has been created using a set created by someone on DAC (Diecast Aircraft Forum). He created individual A4 sized sheets which can be put together - and he did this on Word. I basically exported all the ones I wanted to photoshop, and them together in this layout and had it printed on photo paper, so that its in one piece and the printing is durable. Then I had the sheet laminated and pasted onto MDF/Wood board. The layout has a small taxiway with grass on both sides. The taxiway has two entry points to the apron, which has four gates. The gates are sized to accommodate all aircraft easily - although if I put four A380s on it, it becomes a tight fit! I can email you a jpg of the diorama if you want - the actual file I used for printing is 110MB!
This picture shows some of the details of the gates, taxiway lines, etc.
Here's one more pic - I've been experimenting with adding jetways to the scene. This is one of the initial shots.
The models are priced between $25 and $30 generally, depending on where you're buying them from. www.jetwaymodels.com is a good source for 1:400 and 1:200 scale models - they stock Dragon Wings, Phoenix and Gemini Jets. You can also try ebay, where you can find good bargains at times.
A good collection of PIA models is also available from Aeroclassics, such as this version of AP-BAK:
The picture doesn't show a lot of detail, but this Aeroclassics model is absolutely stunning - and that gorgeous livery helps!