For the younger folks: Kerry got some seriously badass medals for his military service in Vietnam. People who had been on the same boat as he did, but at a different time, worked with the Republican party to claim that he hadn’t really done what he did. The press ate this up, and distributed it widely, costing him public support and likely the election.
Bush did have the advantage of having pictures of him flying fighter jets in an era when the mainstream pretty much worshipped anything to do with military hardware. IIRC he even flew a fighter jet and landed it on the carrier for that infamous “mission accomplished” photo op.
Even though the times have changed a bit, I bet that Trump would get a boost if he could fly a fighter jet. Not sure if he’d even be safe to be a passenger on one unless they kept the throttle at like 20%.