I am ok with giving the people to have an option to wear a mask or not and they can divide accordingly. I wouldnt reserve space up front as it may cause one group to be preferred over the other, but i do like the idea of saying masked people sill in starting from one end, unmasked from the other. Meet at the middle.
Planes id be more reluctant to do it that way, but id be ok with it if again it was divided front to back or something sure.