what is the best material to use to scratch build wings?, plan on convert a heli kit to a sci-fi dropship kinda thing?

If you are making a Sci FI kitbash sort of thing, the best way to get wings is to buy a cheap kit that has wings near what you are looking for and chop them to fit. They'll have the right sort of detail, they'll be symetrical and they'll be much easier to do than scratchbuilding them yourself.

If you are in a club, ask the members if anyone has old, built aircraft models they might want to dispose of by giving them to you and then you can remove the wings as need be. If you can identify the style of wing from an actual aircraft, you can ask if someone has that kit to give you the wings from.

There are a lot of ways to get generic wings that don't involve scratchbuilding them yourself.

HTH

Paul

The other way , is to cut the airfoils glue them with a beam (wing spar) that goes through them at a certain distance. Fill the space in between with some soft scrap material like sponge or balsa or plyurethane foam. Use the car body kit over the surface & then sandi the smooth with the sanding block. You need to be precise when you make plans & cutti airfoils.
If you dont have good plans, you could cut the wing of the same aeroplane kit but in different scale, draw them on a paper. Hope you get the picture.