Despite what airlines are saying as far as safety on the plane the real problem is the airports themselves. People in close proximity in waiting areas, bathrooms, TSA lines, and luggage carousels. Ever see people crowd around a luggage carousel. Everyone is in hurry to get their bags reaching over each other. People grabbing the wrong bag with their bare hands. How about the TSA line where your putting your belongings in trays. People taking off their shoes putting them in the trays. Try spacing that area out. Airports used to be so packed with people that you could barely walk down the corridors. People impatient lining up to board. Again how do you spread those lines apart when people are filling up those corridors. This isn't a big deal now because airports are still relatively empty. Don't compare this 9/11. Travel then was impacted by fear but that fear was unwarranted. The only thing that came out of that was security inconvenience.
Business travel has it's heart cut out. It won't return because teleconferencing and working from home is the new norm. It might never return even after a vaccine. Business people still have to travel because there are so many aspects where the person has to be there. But not like it was before February. That leaves recreational travel. People are still going to go on vacation. But where is the disposable income that people use for travel going to come from if there aren't as many jobs and businesses are earning much less.