If you want to enlist for an MOS that can go airborne, here's how to do it.
Go talk to a recruiter. If you're fully qualified (mental, moral, physical) and jumping out of a high performance aircraft is something you want to do, don't go to the MEPS and hope the job is there, then try to be a tough guy and say you won't enlist unless you get airborne. There's no reason for that to happen.
Tell the recruiter you want to use FSR2S. He'll bust out his laptop to reserve you an MOS. If the MOS and airborne (option 4) is not there, he needs to call the ROC. He'll know where to find the number.
He talks to a guy at the ROC and they pull an airborne slot and email the Temporary Reservation to him. You now have seven (7) days to join the United States Army and begin a career of drinking beer and running every day, maybe shooting some stuff, and falling out of an airplane going really fast.