Rules Clarification:
During Non-Combat Movement a land based unit (Infantry, Tank, Artillery etc.) can enter a Landing Craft unit which belongs to an allied Nation - and which is present in the same territory from the beginning of that turn.
Example:
An Italian Infantry unit in Greece enters a German Landing Craft unit during the Italian Non-Combat Movement phase in Early 1941.
On the German players turn in Late 1941 during Combat Movement, a German Panzer unit enters the same German Landing Craft unit.
The German Landing Craft unit attacks Caucasus - and the German Panzer unit is offloaded from the Landing Craft unit to participate in the attack.
The Italian Infantry unit must stay onboard the Landing Craft unit.
In this case the German attack is succesful - and Germany captures Caucasus.
The Soviet player fails to re-capture Caucasus in Late 1941.
During the Italian players turn in Late 1941, the Italian Infantry unit can choose to be offloaded in Caucasus from the German Landing Craft unit during the Italian Non-Combat Movement phase - or stay onboard for further transportation.
Note:
During this process the Italian Infantry units is considered as cargo for as long as the Infantry is onboard the Landing Craft unit.
If the German Landing Craft unit is lost, the Italian Infantry unit onboard is also lost and removed from play.