School. Air travel.
Those are likely candidates. Let’s see how it plays out.
Once we have 3+ vaccines approved, there will be more choice out there so that people would trust at least one of the options. In addition, upon approval of each vaccine, the stockpiles of doses of that vaccine would immediately become available for distribution.
Besides for Pfizer and Moderna , I’m not sure when the other vaccines that are in US-PIII trials are likely to he approved.