Masks are a good thing in the winter when it's very cold. They are still required on planes and trains until September.

News Alert April 30, 4:16 p.m. EDT

TSA extends mask mandate for planes and public transportation in U.S. until September The Transportation Security Administration said masks must be worn at train and subway stations, bus terminals and airports nationwide, as well as on planes, trains and other types of public transportation until Sept. 13. The previous order had been set to expire in May. Read more

Someone wrote this comment which I agree with:

As a customer of airlines, Amtrak, and local transportation, I applaud this decision. It has been six weeks since I got my second dose of the Pfizer vaccine, so I am fully vaccinated. However, there are too many people who have indicated that they will not be vaccinated to be universally safe. With COVID-19, the variants are a big unknown that could escape vaccines and the resulting antibodies.