As PVB beat me to it- A great place to start is actually using the search function.
Last year I put togethere a 98% accurate Dropship pilot- the only thing missing was the extra bits on the helmet. Here is the thread (with pics):
viewtopic.php?f=3&t=4547&hilit=+dropshipI was going to mention in the other thread about cost- really cost boils down to how accurate you want the impression to be. Someone had mentioned that the cheapest, easiest uniforms would be a synthetic (Bishop) or a Dropship pilot. Well to a certain degree this might be true-
For instance let's take Bishop: all you would need is a dark blue jumpsuit with one Sulaco patch on the left shoulder right? Well if you wanted it to be accurate you would need a set of Reebok Bugstompers shoes as well. Those are RARE and would fetch probably hundreds of dollars on ebay (which would most likely be the only place you are going to find them). You might want to also grab a three way emergency flashlight- again the accurate ones are rare and only on ebay (if you don't come across one in a second hand shop).
My point is that a Dropship pilot might seem easy and cheap on the surface, but in reality can cost nearly as much as a decent rifleman impression.

What you would need is an RAF MK 11 flightsuit. These are becomming more and more scarce. I was lucky enough to grab one off ebay in my size. Cost isn't huge with these, just finding one.
Next you need patches- a Sulaco and Colonial Marines patch on the right shoulder, an American (or British) flag on the left shoulder, your nametape above the right pocket, and a Victory By Wings patch above the left pocket (Ferro) or on the pocket itself (Spunkmeyer). The patches are available on ebay however accurate ones are best found by asking around here.
The boots- Ferro and Spunkmeyer did not wear jungle boots. They wore all leather combat boots (probably early Vietnam era US leather boots). I purchased a pair of black Corcoran jump boots.
The vest- it is a US issue M1969 flak vest; the same as Drake's. I already had one for my PIG Gunner impression so it does double duty for my Dropship pilot (the patches are incorrect on my vest for a DS pilot though).
The Helmet- an accurate one is a Gentex SPH-4 helicopter pilot helmet. Your best bet on finding one is ebay (a surplus store might have one so look there first- but they might charge a ridiculous amount due to it beomming rare as well). On ebay these can go from $100 to $400 dollars depending on the condition. I paid $285 for mine and it was in fairly good shape.
You can get a VP70 but you'll need a accurate holster from Men At Arms- I really don't bother with the VP.
For futher accuracy you need some 80s style mirrored aviator sunglasses- I bought mine for less than $20.
And to finish the impression I went with fingerless leather gloves. Ferro just wears one on her right hand but I didn't want to go with the Michael Jackson look.
Like I said the impression I made was about 98% accurate- and expensive. The cheap route would be-
Generic green flightsuit
Black leather boots
Generic flak vest (Israeli issue is a close copy)
No helmet
You could probably do it for less than $150 this way.
Hope this helps.
Kevin