EDIT: WillyJ helped me fix this. If you run into this problem, check your build.gradle file and make sure you have everything set up properly!
So my content pack is almost done... almost. I have a quasi-working version that I'm able to load up on my other computer and play around with. There's just one problem, and it's sort of a big deal: my helicopters, which work fine when I launch through Eclipse, aren't working remotely in MC, despite all cars, trucks, and planes working fine.
Now here's the REALLY fun part: when I open the jar with WinRAR, there's no com folder. Seriously. It doesn't exist. See for yourself:
The pack works in 1.7.10. I can hop in any car or plane and drive/ fly around. But when I try to place a helicopter, nothing happens. No crash, no model, just three little dots on the ground where the wheels/ skids are supposed to be. It's as if it's looking for a model file that it can't find. That makes sense, since there isn't a com folder. So how are all of my others cars, trucks, and planes working without an issue? Where are the models being stored if not in the com folder? What the heck am I missing?!