I have found out alot of my players have found they can harvest the chinook with 1 C4 and harvest it like the heli so they just spawn blow up, spawn blow up. Is there a way to make the CH-47 non harvestable or a way so they cannot respawn there chinook if they blow it up for harvesting? Thank you.

It is possible.  We have a custom plugin on our server that makes minicopte rand chinook non-harvestable for just that reason.  I would give it to you but it is actually piggy back'ed in to a much more complex custom plugin I am not willing to share.

Not trying to be a jerk by the way, just letting you know it IS very possible and our plugin guy added that feature for us in a mere few minutes.  Maybe someone out there that knows how can show you easier.  Just trying to let you know it is definitely an easy possibility