Ever carried a weapon?
an M16 fully loaded only weighs 4kg. Your pilots weight varies by that much over the course of a month due to fluctuation in water retention. The extra body armor youll need to absorb all the hits you are going to take is going to be heavier than that. And if you cant target and fire while flying, assuming your pack is of a design that frees your arms, your ability to lock dynamic targets is questionable. The laser guided weapons arent much use against the guys running around on deck shooting at you....unless you intend to blow the ship up with a missile...in which case....why are you trying to fly around it? Just send a drone in