In the Air Force when I was in my early 20's I had the opportunity to travel to Cambodia, Thailand, and Philippines. I felt what it was like the be in the 1% of men in the US. It was a lot of fun but very overwhelming and then downright depressing when I got back to the US.
To answer your specific question, probably Tinder or any app near a base. There is an overabundance of young military men and plenty for women to choose from. 80/20 Pareto principal still applies. If you joined the military for the purpose of getting laid, you were wrong. College campuses have way better ratio's. Being a veteran doesn't really score you any points on the attraction scale. Maybe for your TRICARE and BAH.