Health officials are worried about a potential rise in cases after people travel for spring break.
TSA said more than a million people a day have passed through security checkpoints in recent days.
Sunday reached nearly 1.3 million. That's the most since January 3.
Looking at these numbers, the mayor of Miami Beach said he's concerned about the potential spread of the coronavirus.
"We still have sometimes dozens of deaths a day in our county," said Mayor Dan Gelber. "At the same time we have got incredibly cheap round-trip tickets, $40, discounted rooms and people are feeling cooped up and no other place to go than here."
And health officials agree with the mayor. They believe spring break travel could accelerate the spread of variants.
The CDC is also urging people not to travel unless it is necessary.