Each mission sets primary and secondary objectives, but once completed, the powers that be have no qualms about reassigning you six or seven times throughout the course of any given battle. Bomb this destroyer, shoot down that bomber wing, make my bloody sandwiches. It’s pretty relentless. But there is a pay-off for all this hard work. At the end of each mission you are awarded new and better aircraft. Upgrading your various aircraft types to sub-models with better guns or faster engines becomes something of a strategic challenge.