The Side Fighter is a recurring item from the 1940 series which appears in almost all games, the sole exception being 19XX: The War Against Destiny. It is represented by a small fighter icon.
When the player picks up the Side Fighter item, two smaller fighters will join the player, each staying on one side, and mimic it's movement. The side fighters will fire whenever the player's ship fires, effectively raising it's firepower, and also protect it's sides from damage.
In 1944: The Loop Master, they will be automatically replaced whenever one is destroyed, as long as the player have any in stock. They can also be used as a makeshift bomb if the player has none left, as they kamikaze onto the enemy and explode.