I know that this is such a beginner thing to ask help for, but i would really like to know how i can add a hanger from one of the space maps to a ground map that i am currently working on. Any help is appreciated!

It depends on what exactly you are trying to do. If you want the actual hangars used in the capital ships, they can be found in C:\BF2_ModTools\space_template\Worlds\@#$

You want to look for, rep_assultship_hallway, all_cap_rebelcruiser_hallway, or imp_cap_stardestroyer_hallway.
You may want to look at the models in the MSH Viewer before trying to add them to a map; they may not be exactly what you are looking for.

You could also use the Echo Base hangar assets from Hoth, which were intended for a ground map in the first place.

I'm working on a Sullust map that is similar to the 2015 EA Battlefront map. Not sure which hangar would be best but i know that the Hoth hangar is probably too small. Thanks for letting me know, it helps a lot

EDIT
Do you know where the TGA file for imp_cap_stardestroyer_hallway is located?