Battlestations: Midway/Shortage of Reinforcements

By far the easiest challenge mission of them all, Shortage of Reinforcements puts you in command of a squadron of five Ki-45s. Performance-wise they are not as good as the Zero, but their cannons are all mounted on the nose, allowing you to shoot down enemy aircraft with ease.

Primary Objectives:
 * Sink all enemy cargo ships

Secret Objectives:
 * All squadron members survive

A Herd of Buffalo
The only major complication in this mission is a few squadrons of F2A Buffalos. If you've managed to outfly the rest of the campaign, these Buffalos shouldn't be an issue - fly against them like normal. The only danger these Buffalos present is if they stall you long enough that the transport leader escapes, causing you to fail the mission. Therefore, it may be wise to bypass a fight with the Buffalos and deal with the lead transport first.

Either way, you should deal with the Buffalos, sooner or later. Once the buffalos are dealt with, all that remains is sinking the enemy transports.

The Cargo Ships
With the buffalos out of the way, all that remians are the cargo ships. You don't have bombs to bring the hurt on them, but you can definitely strafe them. Your forward-firing guns is all you need for this mission. Instead of shooting at the superstructure, shoot at the flat areas - the cargo containers on cargo ships, the flat area on the bow or stern on transport ships, or the flat middle section on the tankers. Shooting these will cause their cargo to rupture and explode, sinking them in short order.

Starting with the northernmost cargo ship and working your way southward, the cargo ships should be easy targets given their low speed and high surface area. The only danger now is crashing. Some of the cargo ships have a machine gun on them, but it is quite inaccurate and causes low damage - shooting it with your own machine gun will destroy it in short order, but it is quicker to simply target the ship's cargo and save yourself time.

Once all enemy transports are no more, the mission is complete.