Source: US FAA
The Centers for Disease Control and Prevention (CDC), the Transportation Security Administration (TSA), and the U.S. Department of Transportation (DOT) remind the traveling public that at this time if you travel, you are still required to wear a mask on planes, buses, trains, and other forms of public transportation traveling into, within, or out of the United States, and in U.S. transportation hubs such as airports and stations.
CDC guidance is clear that fully vaccinated people are safe to travel and can resume travel.