The stock planes on IJ is way too big IMO and it simply looks like piece of shit. So I searched the web for a mod and only one I found was a spinning propller mod while keeping the same fugly biplane for around $100 and no mod for fighterplane. Why not just make one myself?
So I purchased these 1/72 scale model kits from amazon.
http://i1159.photobucket.com/albums/p633/v4vendetta/Screen%20Shot%202016-02-05%20at%204.17.25%20AM_zpsorz6bl7e.png
http://i1159.photobucket.com/albums/p633/v4vendetta/Screen%20Shot%202016-02-01%20at%206.16.44%20PM_zps8hxec4yf.png
The stock planes are about 1/48 scale. Here is a picture for size reference.
http://i1159.photobucket.com/albums/p633/v4vendetta/IMG_0765_zpsivcq5cpw.jpg
https://vimeo.com/154301171

So I airbrushed the planes and put a motor in it and realized that first airball from Indy would probably destroy the planes.
This time I bought same planes but in diecast model. So first, I finished the fighter plane mod to see if it will hold up to the rigors of everyday pinball abuse. And it passed with flying colors. So here it is in action and let me know what you guys think. Now I'm off to finish the biplane!!!
http://i1159.photobucket.com/albums/p633/v4vendetta/IMG_0750_zpsamn7gvzp.jpg
https://vimeo.com/153834349

Thanks for the kind words. It's truly rewarding hearing the complements from real pinheads. Diecast sure is a pain in the ass to work with. The biplane is technically finished but my minor ocd won't let me put in on until I finish painting and adding Indy and his dad with a gun to the biplane.
As for selling, it consumes alot of hours to make one(being little anal retentive about getting everything perfect,aforementioned minor OCD) so I'm not sure if I can mass produce these considering my work hours so only time I really have to work on these are on my days off. I guess if there are enough interests, I could see what I can do.

I used two different motors for each plane. For the fighter plane, I used miniature drone motor I had lying around and for the biplane, the workable space was way more restricted so only motor that I could find that would fit in was a 3g micro servo motor.

I just searched for IJ mod on ebay and that's what I got. I felt the same way you do about the price of the mod but didn't want to come out say anything negative and just put it on blast just in case it might've been a pinsider making those mod and selling it. That's why I said I decide to make my own. Yes it is a simple mod if you want to just keep the stock plane but the reason why I wanted to do a mod in the first place was to get rid of the stock plane. The link you provided looks very similar to the one I used for the fighter plane but there was no way I could fit that in the space allowed for the bi plane.

It was just alot of dremel grinding, dry fitting, repeat till I can get it to fit and afterwards what I found was the motor shaft always came up too short so I had to solder on a longer shaft to the existing one to get it to poke out the front hole on the plane.