Katharine Hope, the veterinarian who was aboard with Bao Bao, said the panda was happy and comfortable.
Bao Bao was born at the National Zoo in Washington to panda parents on loan from China.
Bao Bao is scheduled to leave the zoo Tuesday morning and fly from Washington Dulles International Airport in Virginia to Chengdu, China, on Tuesday afternoon.
Under the deal, all cubs born at the National Zoo must move to China by the time they reach 4 years old for breeding and research. Accompanied by her American keeper Marty Dearie, she looked well.
The zoo staff will help the panda transition to her new home.
"Once Bao Bao the panda completes this month of quarantine, she'll go on display to the public and I welcome everyone to come see her then", research center expert Li Desheng was quoted as saying in the news release. She will have bamboo from her hometown, apple, carrot and steamed corn bread for her welcoming feast.
In fact, most giant pandas around the world are on loan from China, and cubs born overseas have to be sent to the Chinese breeding program to expand the gene pool before they turn four.
Initially she will be cared for by an English-speaking keeper, as she doesn't understand commands in Chinese.
The zoo still has three other giant pandas.
China has panda collaborations with 17 zoos in 12 countries. A lot of them died.
More than 200 giant pandas also live in captivity.
Including cubs, the current population count is approaching 2,060 and mature adults are estimated to constitute 50.5 percent of the total population, according to a report by the International Union for Conservation of Nature (IUCN) in 2016.