The CDC endorsed Monday what has already become a required practice around the country: recommending that anyone traveling on airlines, trains, subways, buses or other public transport wear a mask. If passengers don't comply, those who won't put on masks should be ordered to get off when possible, the CDC says in its interim guidance on the issue. … The only exceptions for not wearing a mask should be for those travelers who take them off while eating, drinking or taking medication; those who become incapacitated for any reason or can't remove their masks by themselves; or when needed to show their identity, such as when traveling through a TSA checkpoint at an airport.