I have two existing characters and when I starting playing with one of those the AI Teammates showed up the first time I used fast travel.
The problem is with a new character I created. I went through the three "find the crashed helicopter" missions, went to the ancient ruins and then went to and entered Erewhon. After getting a couple of missions I left Erewhon, but there were no AI Teammates waiting for me outside the entrance. I tried a couple of Fast Travels and then returned to Erewhon, but upon leaving again I still haven't seen my AI Teammates.
Is this a bug, or do I need to do something else to trigger them? Any help would be appreciated.