Bei Bei takes 'Panda Express' to China

Washington bid farewell to some precious cargo on Tuesday -- National Zoo's Giant Panda - Bei Bei.

The beloved panda reached the age of four years and that means, per tradition, it was time for the panda to move from the U.S. to China, where scientists hope he will help increase the population of his species…

Bei Bei was put inside a travel crate that zookeepers spent weeks getting him accustomed to.

He's flying out of Dulles International airport outside Washington on the so-called 'Panda Express' a specially-outfitted Boeing Triple 7 Freighter jet flown by Fedex to Chengdu, China.

He's travelling with snacks, water and 66 pounds of bamboo, the zoo said. Among his favorite snacks: bamboo, pears and cooked sweet potatoes.

For the past month, the National Zoo hosted a series of celebratory events inviting the general public to bid the panda goodbye, including a Postcard Station next to Bei Bei's outdoor habitat, where guests wrote post cards that will be mailed to Bei Bei in China.

The National zoo has collaborated with Chinese scientists on a breeding program since it received its first pandas in 1972 following President Richard Nixon's visit to China. As part of the program, pandas return to China at four years of age so they can breed when they reach maturity at five.

Thanks to reforestation efforts, pandas have been reclassified from "endangered" to "vulnerable." Bei Bei too may eventually help boost panda numbers, after Friday's bitter-sweet farewell.