Some Americans who are overseas are already having a difficult time returning to the United States because of canceled flights.
On Thursday, President Donald Trump said the military was trying to help some who had marooned in South America, as the State Department flatly sent the message that if Americans don't return now - they may be out of luck for some time.
“If you choose to travel internationally, your travel plans may be severely disrupted, and you may be forced to remain outside of the United States for an indefinite timeframe,” the travel warning stated.
U.S. airlines have already started to drastically cut back on their international service, scrambling travel plans for thousands.
For example, American Airlines already announced it would reduce international service by 75 percent.