Mr. Chen and his family departed around 5:30 p.m. on a United Airlines flight after facing earlier delays. The Chens, accompanied by American officials, were brought onto the plane shortly before takeoff and seated in the business-class cabin. Flight attendants drew a curtain around their seats and barred other passengers in the cabin from using the toilet while the plane was on the runway.

In a statement, American officials obliquely praised the Chinese government for its cooperation in resolving what had become a diplomatic headache for both sides. “We also express our appreciation for the manner in which we were able to resolve this matter and to support Mr. Chen’s desire to study in the U.S. and pursue his goals,” Victoria Nuland, a State Department spokeswoman said…

Mr. Fu, who spoke to Mr. Chen several times on Saturday, said the family had no idea they were leaving — or where they were going — until officials notified them to pack up their few belongings.