The Navy does have a signing bonus. To be eligible for the bonus you must already be on active duty and be qualified as a naval aviator in an aircraft that the Navy flies. Basically when your initial 8 year commitment after getting winged is up, you can get this bonus so long as you meet the above criteria AND have been selected for a department head position within a squadron. Don't meet any of that criteria and no dice on the bonus so you are out of luck if you are coming from the civilian world. Initial commitment for Navy is still 8 years after wings, for fighters at least. I think it is 7 for helos and big wing.