The beloved giant pandas at Washington, DC’s National Zoo started their journey back to China on Wednesday, crated up and loaded into a special “Panda Express” FedEx Corp. flight to Chengdu.

Washington’s three pandas — Tian Tian, Mei Xiang and Xiao Qi Ji — are among others at zoos in Atlanta, San Diego and Memphis also heading to China as an era of “Panda Diplomacy” with the US appears to be ending.

Their flight — on a Boeing Co. 777F aircraft emblazoned with a panda face — from Dulles International Airport departed around 1 p.m. Wednesday and landed about seven hours later for a refueling stop in Anchorage, Alaska. 

Local news stations broadcast live coverage of their trip to the airport and departure. The journey was at one point the most followed on tracking website FlightRadar24. 

While their return to China was known for months, the exact timing had been kept a secret until Wednesday morning. The zoo’s 24-hour panda-cam is now just a highlights reel.  

The US was rewarded with its first pandas after President Richard Nixon normalized ties in 1972, and many other nations followed. Under the terms of China’s wildlife agency, zoos that host the pandas never get full custody. Instead, they rent them, signing contracts to pay hundreds of thousands of dollars every year.

It’s never been clear why the contracts for America’s pandas weren’t renewed. But the timing has coincided with a particular low point in relations between Washington and Beijing over the past few years.

There are signs that things could improve. President Joe Biden and China’s leader Xi Jinping are expected to meet later this month in San Francisco, their first face-to-face in about a year.