The Air Raid Bunker can be found on every map except Coral Sea (since there is nearly no infantry based combat). It can be found on the "Airfield" flags of Wake Island and Iwo Jima and the "Outpost" flag of Guadalcanal.
It can only be used as soon as any team has captured it. From there, any player from either faction can activate the air raid. Once inside the bunker, the player is completely invulnerable and is so until the bombing run is over
The Air Raid Bunker appears in the Battlefield 4: China Rising expansion pack. Similar to Battlefield 1943, the control point containing the bunker must be held by either team in order to call in a bomber, but the bunker can be used by any player from either team. It allows a player to control the Bomber.