I am from VMI. I had a full scholarship so I was guaranteed a commission and had everything paid for while at VMI. You are required to do all the classes and FTX's and such and then you put in your package just like everyone else when it comes to jobs. However as far as the Navy goes, when they rank your packet, they factor in schools and major...so Engineers get extra points, as do certain schools which are known to be "more difficult." VMI is 100% for getting flight slots for Navy guys that have wanted them in the last 14 years or so. Even if you dont have a scholarship, at VMI you are required to do one of the ROTC's, whether you commission or not. Some of the guys in Navy ROTC actually didnt want to commission. In fact, 2 in my class chose to go through OCS about a year after graduating and both got flight slots.
There is a certain number of flight slots that the Navy as a whole allows for ROTC's to send in. Each school doesnt have a specific number of slots, so when you put in your packet, you are up against all the other ROTC people.
If you have any specific questions, feel free to PM me.