The USAF didn't design their cargo aircraft with passenger comfort in mind. :lol: The C5 might be the exception. Fat Albert has a passenger section in the rear of the aircraft up top. It has airline type seats (60???). The best flight I had on a USAF bird was a C5 from Sondestrom Greenland to Dover Delaware. I was on a short TDY to Sondestrom, finished up early, and caught a hop on the C5. Since I was the only pax, they put me up in the crew rest compartment behind the cockpit. The pilot was a Captain I knew when he was a cadet at the USAF Academy so he invited me up to the cockpit and I sat in the jump seat between the pilot & co pilot. Quite the view.
I'm pretty sure they can put passenger seats in the main as well. The only thing is, they face the rear of the plane. Another little oddity of MAC AIR. It is usually the cargo parachute seats though as they usually fly mainly cargo. The old C-141 wasn't too bad of a ride either.
Talk about. I flew in one from the U.S. to Thailand one time. No comfortable seats in those things. Sit on a web seat and stretch your legs out. And the noise! Whew! The C-5 is more comfortable but it is loud too.