KEY WEST, Fla. — In the end, said passengers who fled a cruise ship because of a coronavirus outbreak at sea, the evacuation and journey back to the United States was more harrowing, chaotic and frightening than their ill-fated maritime voyage.

Weak and sick from no food for nearly 24 hours, several passengers fainted. Two went into respiratory distress. Others had fevers so high that they had to be separated from the rest of the travelers aboard the chartered flight. Several had severe coughs.

“This was almost as much of a debacle as the cruise was,” said Jennifer Catron, a former medic who spent the entire nine-and-a-half hour flight providing medical care. At one point, she took over the in-flight announcements and begged passengers to donate spare peanuts to help revive those who were passing out from low blood sugar.

“It was probably scarier than the cruise,” Ms. Catron said of the flight, which landed at about 6:30 a.m. Friday and then idled on the tarmac in Atlanta for about five hours, because health officials learned that three of the evacuees had tested positive for the coronavirus.