A Federal judge in Florida has ruled that transportation mask mandates should not be enforced, so they aren't! A number of airlines, including Southwest, Delta, American, United, JetBlue, and Spirit are no longer enforcing them on domestic and certain international flights. If flights are flying in to a country with a different mandate, masks may still continue to be required on the flight.
Des Moines International Airport is no longer enforcing mask wearing. DART announced that after two years, they will not be requiring passengers on buses to wear masks.
Of course, if you feel safer in a mask, you should wear a mask.