Land Base Aerial Support

Introduction
The Land-Base Aerial Support (tentative name) is a system introduced in the May 2nd-3rd 2016 update along with the Spring 2016 Event, which enables carrier-based and land-based aircraft to be launched from air base and assist you during the sortie.

Prerequisite
Currently, the only way to unlock the air base is to clear E3 and its prerequisites during the Spring 2016 Event.

A second air base can be unlocked by clearing E5 during the Spring 2016 Event. Though E5 is optional, players are recommended to clear E5 before proceeding to E6 for additional firepower.

How To Use
First introduced in Spring 2016 Event, after clearing the Map E3, you'll be able to establish an air base from which you can launch aircraft from. You can launch carrier-based aircraft and seaplanes, as well as land-based aircraft that is exclusive to this support system.

In certain maps where land-base aerial support is available, you can activate the support and assign aircraft to the airbase as shown here:

When the land-base aerial support is active for that map, a mark will be displayed below the sortie button.

At the start of the sortie, you can designate up to two target nodes per airfield where aerial support the will be performed. You can also select a single node in order to concentrate all of your aerial supports there.

When you reached the node where the aerial support is requested, a land-based air battle will take phase before the carrier-based air battle, support expedition and initial torpedo strikes. This allows them to weaken the enemy air fleet and weaken their air power, allowing your fleet's air force to secure air superiority more easily.

If you have cleared Spring Event E4, you'll have an additional airfield to accommodate more aircraft, allowing you to target four nodes instead of two. Clearing Spring Event E5, will unlock the 3rd airbase fleet/squadron.

Similar to the shipgirls, the air fleet that are assigned to the air base needs to be resupplied as well.

The refueling process for aircraft is similar to the refueling the shipgirls.

Options
There are 5 options in the airbase menu as shown below:



Those options are, in left-to-right (for pictures above) to descending order (for description below):
 * 【出撃】 Sortie
 * 【防空】 Air Defense
 * 【退避】 Retreat
 * 【休憩】 Rest
 * 【待機】 Standby

Choosing sortie (or standby?) will allow you to choose nodes you want airbase support. Choosing Air defense will skip the choosing node process but supposedly AA combat throughout your sortie, so you should only choose Air Defense mode with AA planes equipped at the airbase. Retreat is currently unknown. Rest supposedly means you don't want airbase support at maps where you can use it and thus you'll not have an option to choose which nodes to attack.

Limitations

 * Each aircraft has their own "flight range", which indicates the combat radius of the aircraft. Aircraft that has low flight range may not be able to effectively support the map nodes that are too far away from their air base.
 * The Land-Base Aerial Support is calculated separately from Opening Airstrike and Support Airstrike expedition, and aerial conditions from one phase will not be carried over to subsequent phases. Securing air superiority or better during Land-Base Aerial Support phase can will weaken the enemy fleet's air power, reducing the required air power to secure air superiority for your fleet.
 * The air fleet may become demoralized if your fleet does not reach the node their supports are assigned to.
 * Changing the aircraft, you'll see 配置転換中 on the aircraft you switched off because it is "transporting/relocating" that aircraft you just switched off and will take 15min (?) until you can choose that plane again. Thus, don't change your aircraft too often.

Trivia

 * When the system was first implemented on May 3rd 2016, there was a bug that caused the bombing damage from land-base aerial support to be omitted from internal enemy HP damage calculation, which occasionally causes a supposedly sunk enemy unit to be able to act as if they were alive (able to attack/be targetted by your fleet), as shown here
 * Also, this is where the map/atoll for Spring 2016 event. 2016spring_event.png