Comment by stateofinquiry

I'm not sure if you are saying one can or can't express opinions on airliners.. but I do want to point out that the "contract of carriage" of most airlines is more restrictive than you might find for a ticketed event like a concert. You might want to read the one for United, just for fun (especially if you fly). https://www.united.com/en/us/fly/contract-of-carriage.html Rule 21, item H 16 even indicates that you can't smell bad. YMMV, but it is pretty far from a "public" space as I define one.