United Airlines Flight 869 took off from San Francisco on Thursday and arrived in Ho Chi Minh City, formerly Saigon, shortly after 10pm local time (1500 GMT) on Friday.
It was the first US commercial plane to touch down at Tan Son Nhat International Airport since the wartime capital of South Vietnam fell to the communist North in 1975.
VIPs emerging from the blue and white plane were greeted by Vietnamese women wearing traditional white tunics or ao dais, and holding lotus blossoms and silk lanterns.
US-Vietnam relations have improved considerably in recent years. The two countries established diplomatic ties in 1995, and in 2001 they signed a landmark trade agreement, followed by an aviation pact last year.
United Airlines, which filed for bankruptcy two years ago, is betting the daily flight to Vietnam will be a big money-maker. The carrier says it expects air travel to Vietnam to grow by 10.5% a year in the next decade.
Many Vietnamese living in the US
are likely to use the service
Among the 347 people on the flight was 48-year-old Van Trinh, one of the tens of thousands of Vietnamese who fled the country in boats after the war.
"I'm excited to see Vietnam now because 30 years is too long," she said before boarding the Boeing 747-400.
Trinh is among 1 million ethnic Vietnamese who live in the United States, the largest population outside Vietnam. Many visit their homeland every year.
"The United Airlines link between the two countries will not only serve Vietnamese nationals living in America, but I was told that 45 million Americans wanted to travel to Vietnam, and that is a very big market," said Nguyen Xuan Hien, Vietnam Airlines president and CEO.
Meanwhile, Vietnam's state-owned airline has expressed interest in opening its own route to San Francisco by the end of next year, or early 2006.
"The new United Airlines route is a new indicator of the strong relations between the United States and Vietnam," US ambassador to Vietnam Michael Marine said.