Just wanted to know if it is possible to add H3 objects such as jet packs and vehicles into halo ce?
Thanks in advance for any help.

You can add objects that are identical to H3 objects, but as to actual h3 files that you would get directly from the Halo 3 game, I'm pretty sure you can't, since you can't even play Halo 2 maps with Halo CE.

Yes but it won't be as simple as copy-paste. First of all you would need to rip the 3d model and bitmaps from Halo 3. Create some new shaders, then either re-rig the model to work with the default animations or create new animations your self. Depending on what your porting you might need to create a new collision model.Lastly some things like dual gunner seats in vehicles don't normally work in CE. There are work-arounds but they're not perfect and have some problems of their own.

Thanks for the replies.What i noticed in the models section were h3 models and i was basically wanting to know if they were ready to use in ce maps or what i needed to do to make them work.I am rather new to this but am wanting to make a version of the sandtrap map with new equipment and such.I am also considering a new warthog version.Any help is very much appreciated.I will b using 3d studio max and i already have the other programs i need.This site is the best and the ppl here are too.

Your best bet would be to look up some tutorials on creating and tagging weapons and vehicles. However since they were only released as models and not tags, they most likely will require some work before they will be ready to go in-game.