If I may suggest, make a prerequisite tech with a basic non-combat light-weight heli that is a bit slower and cheaper with perhaps no RC ability.
And at the opposite end, a later and very much more expensive (and/or require space science?) superior heli with some more capability and futuristic/sleek design (VTOL or not) that lands/lifts-off faster with better breaking power and (toggle-able?) auto turret.

[Might only currently be a 1 piece, 2 assessory set, but a wonderfully made mod. Lift/land realism, water and ground effects from lift force, working speed AND fuel gauge! AND can called/told to follow self or a player of choice, land at position (self or placed) and fly to location tags/map markers? Super, stupidly useful and functional! Not much gets my interest, but with this little addition, color me impressed. I will use this mod from now on as long as it exists. Can only hope for more.]

@HappyBroccoli what would you need to make a VTOL? Specifically? I have a friend who does Graphic design who might do me a favor.

I'm not too familiar with animations, but I believe I need Images of the vehicle turning at various degrees. I think it needs 64 directions for a vehicle to turn.

@HappyBroccoli so you could not do it with the blender file? let me look into it

I'm not experienced with blender, but I believe you make the 3D object, and save images of it rotated. Sorry, I'm on my phone right now, I can't go too I to it too much. When I get home from work I'll see if I can find some more info.

I've been picking up extra days at work, I haven't had too much time the past few weeks.

There is an excellent guide here https://forums.factorio.com/viewtopic.php?t=5336
Bit old but thats how I did it.

Thanks for that link. I just got home, and I'm reading through that now. Time to install blender xD

I should be able to work with a blender file. I spent last night watching tutorials and getting acclimated to the interface. With the tutorial kumpu provided, I should be able to do what I need to get the sprites made.

I have much to say, I could write an essay's worth, but no. I am too busy as is to make content for other games with my own MMO I am making. So in short, thank you wonderful people for at least trying to see if this wishful idea for this wonderful mod is feasible. I am not used to an unusually intelligent and like-minded and helpful community like Factorio's that like to make things happen (mostly fixes from authors, but still... that's more than I can say about other groups).

Thank you arkcane for pushing to get the ball rolling. Thanks kumpu for the helpful link. And last but not least, HappyBroccoli for continuing the project the best you can.

@HappyBroccoli I haven't given up, but I am leaving for a trip shortly. I have poked a couple of concept/3D modeler friends but until then you want you could use.

https://free3d.com/3d-model/air-drone-910668.html
or
https://free3d.com/3d-model/intergalactic-spaceship-in-blender-28-eevee-394046.html

both of which are free.

@arkcane Hell no, all models have to look 100% vanilla ;) That's why this is so hard. And why I went for a russian heli with the current model, russian gear often has this weird look to it.
Anyway I'm back in the country now. I don't really play the game anymore but expect some updates. And a big thanks of course to everyone who contributed :)