I joined a flight club and my trainer showed me his man cave of planes and tools he's had for 20 years of building. I'm a mechanic, auto body guy and a car racer, so I also have many tools.
So, what tool or tools would even he may want or need, that I can buy for him ? I did not look in his tool box or his caddy bag of tools that he goes to the track with. But nothing real expensive guys, he's not worth that much. lol

I know his small screwdrivers suck ! lol

If he is a serious builder and doesn't already have one, get him a Wil-Kro double edge razor blade planer. It has not been manufactured for many years but can still be found on eBay for $20 to $25. They work great for shaping balsa and foam. It creates a pile of shavings on the floor instead of clouds of respirable dust in the air. A quick Google search for "Wil-Kro razor planer" will get you a picture and sites that have them for sale.

Thanks bud.

I’ve had a Wilkro plane for decades and it is a great product. But for probably 20 years or so, I’ve had several of the Master Airscrew razor planes that work as well as or better than the Wilkro. I’ve modified a couple of the MA planes for special applications like planing into a closed corner, etc. Cheap and effective.

You could start by buying him a set of Wiha small screwdrivers. I love their stuff.

I bought a set three years ago, and love them too. If the green color is ok. lol

Every WiHa tool I've bought had a black handle with a red cap.

Mine are green.

So are all of mine, but the ones that I bought as a set came in a green fabric case. They even fit the JIS screws on my Blade 230S helo, acceptably well.

Maybe I'll just get him some duct tape.....

(well since we are talking model airplanes maybe a roll of packing tape for patching covering..)

Scroll saw, bench top belt sander, drill press, sanding blocks, lots and lots of pins, tacks, x-acto blades and so on.

Good ideas.