CHANTILLY, Va. — One month after winning federal approval for a coveted nonstop route to China, United Airlines launched its inaugural flight yesterday from Washington's Dulles International Airport to Beijing to the applause of passengers.

"Flights from the United States to China are always packed," said Matthew Alesse of Buffalo, N.Y., whose work in the medical-device industry takes him to China about four times a year. Passengers say more flights are needed as commerce between the nations grows.

Previously, he would fly to China through Chicago, where bad weather sometimes led to delays.

Direct routes between the U.S. and China are strictly rationed by international agreement, in part because of busy airports in China and a desire to protect domestic airlines there from competition.

"China is a lucrative and growing market that is tightly restricted in numbers of flights," said Mark Treadaway, vice president for air service development at the Metropolitan Washington Airports Authority, which runs Dulles and Ronald Reagan National airports.

When a new slot opened up last year, airlines and airports waged what airports authority President and CEO James Bennett called "an old-fashioned, junkyard dog fight" to land the new route.

Northwest wanted to fly from Detroit to Shanghai. AMR Corp.'s American Airlines wanted to fly to Beijing from Dallas, and Continental Airlines Inc. touted a Newark-to-Shanghai route.

Ultimately, the U.S. Department of Transportation awarded the route to UAL Corp.'s United, which talked of the benefits of a direct flight between the nations' capitals.

Bill Zhao, a Beijing resident who returned home from business on yesterday's flight, said it was the right decision.

"Almost everyone who comes to the United States from China, they will want to see the U.S. capital," said Zhao.

Zheng Zeguang, a Chinese embassy minister who attended special ceremonies at the airport yesterday, said the new route increases the number of weekly flights between the two countries from 105 to 119.

Asked about allowing even more slots given the intense demand he said, "We are working on it."

The flights will do more than facilitate business, said Virginia Gov. Timothy M. Kaine.

"This connection will bring wonderful economic benefits, but most especially will bring cultural benefits and ties of friendship," Kaine said.

Among yesterday's passengers were fifth-graders from a Chinese language immersion program at Potomac Elementary School in Potomac, Md.

Pupil Ben Ertman said he was eager to try out his Chinese in Beijing, though he was unsure if the Chinese he learned in class would translate in real-world conversation.

"I'm kind of worried about it," he said. "But I'm excited about seeing the Terracotta warriors (life-size statues created more than 2,000 years ago for the tomb of China's first emperor) and the Great Wall."

United will use a 347-seat Boeing 747-400 on the route. Roundtrip prices ranged from about $1,000 for economy class seats to $14,000 for first class on the 13 1/2-hour flight.