Why are we debating this development? If sitting shoulder-to-shoulder beside strangers for the duration of a flight is above your comfort level - do not fly. There was no surprise from the very beginning of this pandemic that airlines would return to full-capacity seating prior to an effective vaccine being available and administered to the population. We're about to reach that date, and it's understandable that some passengers will feel more comfortable than others about the reduced separation. Flying remains optional and the airlines have no ability (nor obligation) to ensure you or your planemates don't bring along a case of the 'vid to the flight levels. Those asking for medical studies and research may not understand that a) thousands of such studies are ongoing and b) there is still so much the medical community doesn't understand about covid and its transmission.