If it is just business travellers and millennials, many airlines will not survive
True, that's why some Airlines just like KLM video example before, try to convince more customers back to flying. Most Gen X have more money than millennials for example, that Gen X can bring their family and buying premium tickets then most millennials that will try to find budget offer.
However, the tendencies of Millennials to travel so far being shown their willingness to book tickets and hotels to tourists destinations area after lock down. Talking to Travels Industry in SEA region for example, shown bookings that begin flowing back on tourists area in Thailand, Singapore, Malaysia and Indonesia dominated by millennials segment. In fact data from Bali for example shown tourists that choose to stay in Bali during the lock down mostly are millennials. Some of them choose to "work from home" from Bali.
Millennials will be like "show case" for Gen X and Boomers to see if traveling already safe or not, in my opinion. The tendencies of this population segment to be more 'daring' make them perfect 'baits' by Airlines and Hotels to attract bigger pockets segment to back on traveling.
For that if you see the offering from Airlines and Hotels right now on onlines are shown more budget 'concius' offering to attract more millennials back first. Cause the industry knows it will take more time for 'more mature' customers back on traveling.
They have to start somewhere on attracting customers back.
Masks on a plane definitely strike me as something to make people feel better and safer without any real protective value.
That's why they are showing something else, their effort to produce better air circulation system (as they claimed). Most customers worries are on safety of the airline air circulation for filtering potential patogens during hours on board. If some segment of travellers begin to come back and they manage to shown the effort by Airliners for 'new normal' travels are relatively save, than more segment of population will be back on traveling with Airlines.