Thanks for the pointers! I just fixed the entity and now is working

Must say you guys are doing an outstanding job with this game, the new mechanics, the items, especially the bigmaps... if you keep treetops and you have a good silenced sniper rifle, man this is amazing.

Thanks again!

EDIT:
Also, it did not require a new game, I was able to use an old save from before getting Skyrider and the chopper worked.