Battlestations: Midway

This must be earned in a Multiplayer game. The legit method is to have an awesome team, and make sure you kill 5x as many units as the enemy does. Killing planes will greatly improve your ratio because they give you many kills quickly.

The alternate boosting method is to load up a private match and simply kill all of the other player's units, then complete the match. Whether you win or lose, it doesn't matter as long as you killed 5x as many units as the other person did (ideally they shouldn't kill any of your units).