Looking for a small ship oxygen solution for passengers

Hey guys, I was building myself a small shuttlecraft like ship and was having trouble figuring out how to get Oxygen to it's crew and passengers. Last time I checked small ships couldn't hold oxygen, so I was wondering if you guys knew of any mods that feature something like open seats connected to oxygen or perhaps a workaround to my problem.

Edit: You guys have been super helpful, thanks a bunch.