Vietnam Airlines, low-cost carrier VietJet and recently established Bamboo Airways are preparing to operate non-stop flights, reducing travel time by almost eight hours.

Flights now take 20.5 hours to fly from Ho Chi Minh City to San Francisco via South Korea's Incheon International Airport, while the planned direct service to major cities along the U.S. West Coast would take only around 13 hours.

In February the U.S. Federal Aviation Administration (FAA) granted a Category 1 rating to the Civil Aviation Authority of Vietnam (CAAV) under its International Aviation Safety Assessment program, which means the latter meets safety standards to operate flights to the U.S.

In February two of Vietnam’s low-cost carriers inked deals worth a total of $21 billion with U.S. corporations when President Donald Trump visited Hanoi for his second summit with North Korean leader Kim Jong-un.

Budget airline VietJet struck a deal with U.S. aircraft manufacturer Boeing to buy 100 new narrow-body 737 MAX airplanes for $12.7 billion and with General Electric for long-term engine support and maintenance for $5.3 billion.

Bamboo, which began flying in February, also inked a deal with Boeing for 10 wide-body 787-9 Dreamliners worth almost $3 billion.

Vietnam Airlines is considering buying at least two new long-range Boeing jets in preparation for beginning services from HCMC to Los Angeles or San Francisco in California state in 2020.

Vietnam Airlines is eyeing the Vietnam-U.S. West Coast route, on which an estimated one million people fly every year, "the biggest unserved nonstop route," it said.

Its CEO, Duong Tri Thanh, said: "In the airline business, the longer the route, the more competition you face."

It would take at least five years for the direct service to the U.S. to break even, and there could be an annual loss of $30 million in the first few years, he said.

Vietnamese airlines will probably start with flights to San Francisco and other cities with large Vietnamese communities and then gradually expand to other major U.S. cities like Washington, D.C. and Chicago, the Nikkei Asian Review reported.

There is large demand for travel between the two countries. The number of Americans visiting Vietnam grew by 11.9 percent last year to 687,000, according to the Ministry of Culture, Sports and Tourism.

An ethnic Vietnamese population of over 2.1 million in the U.S. is also expected to be a steady source of travel demand, industry insiders said.