Plane Management

Together with the pilots, the planes are what makes an air unit. Finding out the status of your aircraft is easy and can be done in a number of places. The list of air units at a base will display the number of ready, not ready and reserve planes for every unit. The unit information screen will give more information, splitting the not ready planes up in those damaged and those in maintenance.

Adding planes
Many air units will arrive understrength or lose planes during the game and these must be replenished. This can be done automatically by the computer if the option "Replacements allowed" is chosen in the unit information screen. If there are planes of the appropriate type available and the unit can receive replacements, the computer will send the maximum numbers of planes to the unit.

The player can also manually choose to add planes to a unit. This is done in the centre of the unit information screen. You can either choose to take the max number of planes the unit can receive, or take them in one at a time. The player can also choose to send a maximum of 4 reserve planes to a unit. This is done in the top left of the screen. Reserve planes will automatically be used to replace damaged or destroyed planes.

Restrictions
There are a few restrictions on the ability to take replacement planes. One of the following conditions must also apply, note that an airfield must have less than 59% service or runway damage to be eligible.
 * Maximum 12 planes per unit
 * A unit can only take replacements once every 7 days
 * Enough planes in the pool
 * 1) The unit is at an airfield with more than 20,000 supplies (No airfield is needed for floatplanes)
 * 2) The HQ of the unit is within transfer range and at an airfield with more than 20,000 supplies
 * 3) The Command HQ of the unit is within transfer range and at an airfield with more than 20,000 supplies.
 * 4) The unit is within twice the transfer range of its HQ or Command HQ and the HQs base has twice its supplied required + the supply cost of the planes and there are 10 + (plane build rate/2) planes in the pool. Then a sub-unit is created at the HQs base.

Supply cost
Supply cost are incurred for each added plane, these seem to be dependent on the plane type. Costs tested so far are


 * 12: Fighter, Fighter-Bomber


 * 15: Float Plane, Dive Bomber, Torpedo Bomber,

Where the cost is incurred depends on which of the conditions was satisfied to allow planes to be added. (So if supplies are short in the groups own base, but planes were added due to a well-supplied base with an HQ, then the base with the HQ will lose supplies.)
 * 30: Light, Medium, Heavy Bomber

Air units on ships
Units on ships have 2 ways to get replacements They also have the added restriction that the ship may not have more than 50 flooding or systems damage.
 * 1) The ship is in a friendly hex with an airfield and 20,000 supplies
 * 2) A replenishment unit is within normal range of the ship and has sufficient planes.

Upgrading Planes
Air units can not retain the same type of planes forever. The pools can run dry or the plane simply becomes outdated by newer models. For these reasons, many groups in the game can upgrade their planes.

There are 2 ways of doing this. Either the group is set to automatically receive upgrades, done in the centre of the unit information screen. In this case the group will upgrade if there are enough planes in the pool to replace all planes currently in the unit. There must also be sufficient AV support in the base. The plane to which it will upgrade is shown in the unit information screen.

To manually upgrade planes, the player will stay have to temporarily allow upgrades. Once this is switched on, the button "upgrade now" becomes available, provided all conditions for an upgrade are met. Upgrade now has lower restrictions on the number of planes in the pool, as long as there is one plane of the new type available it will upgrade.

If PDU is on, the player will have a choice of which plane the unit upgrades to, this choice is made by clicking on the yellow text regarding upgrades.

Finally, the old planes are added back to the pools, though not at once, a delay is added of up to 7 days.

Restrictions
The restrictions for adding planes apply here as well, with the difference that the airfield must be level 7 or higher instead of 1. The needed airfield level can be lowered by the presence of an HQ near the base. If the base's command HQ is within range, then the airfield level is lowered by the HQ's command radius. If an air HQ is within range of the base, the needed AF level is lowered by the HQ's command radius/2, or by 1 if the radius is 1. To determine whether a base with HQ is within transfer range of the unit, the highest transfer range of the old and new plane is chosen.

Supply Cost
A supply cost is incurred for each new plane, this is equal to the one for adding planes. Where the cost is incurred depends on which condition to allow upgrading was fulfilled.

Air units on ships
To upgrade an air unit on a ship, the ship must be in a friendly hex with a level 7 airfield and over 20,000 supplies. This base requirement can also be lowered by the presence of an HQ as for normal air units.