World 6

You can't use Support Expeditions in World 6. However you can use Land Base Aerial Support in world 6-4 & 6-5 once you cleared "LBAS Construction Quest"

Sortie Worlds
World 1: 鎮守府海域	World 2: 南西諸島海域	World 3: 北方海域
1-1 · 1-2 · 1-3 · 1-4 · 1-5 · 1-6	2-1 · 2-2 · 2-3 · 2-4 · 2-5	3-1 · 3-2 · 3-3 · 3-4 · 3-5
World 7: 南西海域
7-1 · 7-2 · 7-3
World 4: 西方海域	World 5: 南方海域	World 6: 中部海域
4-1 · 4-2 · 4-3 · 4-4 · 4-5	5-1 · 5-2 · 5-3 · 5-4 · 5-5	6-1 · 6-2 · 6-3 · 6-4 · 6-5