I'm not sure if it was a shortish book or a novelette in an anthology, I read it in the UK about 2000.
There's a war going on between Earth colonised space and the alien menace, the main protagonist is out in his one-man fighter on routine patrol in a remote sector, then his scanners pick up an alien dreadnought, he yells for help on his FTL communicator and then dives in to attack with guns blazing and missiles firing.
When the squadron arrives they see a destroyed battleship with his craft buzzing around it, he's still pressing fire buttons but his magazines are empty. He's feted as a hero and given the top medal, now he can basically do what he wants.
He's eating in fancy places for free, if he wants a new car the dealers compete to donate their finest machines for the prestige. If he fancies a gorgeous married woman their husband bows and allows it, the woman gladly donates herself to his fun.
It transpires it's a fraud, Mr unscrupulous businessman stumbled across the derelict craft and hatched a plot, then worked through lots of files to find the right pilot who would play along and fake an attack. The businessmen can then use hero's influence for nefarious schemes.
Eventually the pilot takes a brave step, he arranges a private meet with Terran president and confesses all, the president sorts all by getting something (I can't remember) to happen to bad businessman. He then tells fighter pilot that Earth needs military heroes so he'll have to play the role for life.
