The flamethrower has a range of about 5m and is a great tool to counter the Japanese BANZI charge.

You can then advance to a building at the airport on the island and use your rifle grenades to take out the Japanese machine gun positions.
Pick up a Bazooka and destroy the tanks then advance all the way to the airfield and receive a mission to assault the Japanese anti-aircraft gun positions. After taking out the members of the 4 anti-aircraft guns