silverpike.. you are obviously forgetting a lot of people. not everyone in the air force flies a plane. for every plane, there's maybe 1 or 2 people as pilot and flies it, but there are also 5 technicians, then there's the base staff, R&D, military academies.. etc. for the navy, they also have naval aviation, land-sea defence. just to let you know USAF have 7000 aircrafts and 358000 men, that's 51 men per plane. USN have 281 ships and 4000 aircrafts, and over half a million men, then with your 200 men per ship and if 50 men per plane, the numbers still don't add up. and USN would have too many personel in your opinion. but they obviously dont.
also in china, it would cost less to have military technicians than to hire civilians, and the security of information is also easier to ensure with military.
btw, i'm not wrong about the PAP, if the demobilize PLA soldiers go to PAP, they can get some rank, like corporal or serg. since PAP have a military structure. those are the lucky ones. some just serve as regular privates.