I use a faction that does not have any helicopters. So the reinforcements arive by convoy on the ground. But they allways appear at the same spot.
I can't change the location where they spawn
I think the Logistics module is designed to reinforce from a single position. In the Logistics wiki article , it even has a tip how to force this...
Tip: use Military Placement (Custom Objectives) set to very high priority (e.g. 999) to set a custom fixed insertion point.
I don't know how to move the reinforcements insertion point during a mission, but keen to find out if that's possible!
Are you good with script? I feel like your (lack of a) helo issue might resolved through whitelisting/blacklisting units for the force pool. ie: add another faction with helo units to your AI Commander module, change your Logistics module's option from "Faction" to "Side", then blacklist ALL of the 2nd faction's unit except for the helo's... maybe?
When set to dynamic it’ll spawn at held high priority MIL Obj’s (could be just about anywhere), when set to Static it’ll spawn at the closest MIL Obj to the module that’s held. If you want to force a specific spot, set to Static and place a cust obj near the module with high 999 priority.