So here's how I understand the land:
The land takes place a generation after all the conflict in the five movies. Alpha Centurai Expeditions have setup a human friendly area in the Valley of Mo'ara. The ACE travel guides have helped setup the area to celebrate Pandora and the Na'vi, but generally the Na'vi are unwilling or unable to go the Valley of Mo'ara. The notable exception to this is the Na'vi Shaman inside Na'vi River Journey.
At the entrance of the land is the Baja Tickler plant that helps detoxify the atmosphere and make it suitable for humans. However, because Flight of Passage takes guests outside of the Valley of Mo'ara, we need to utilize our Avatar's to safely breath the air. That's why we need to use the link chairs.
Can anyone with a better understanding of the land confirm?