Vietnam is already negotiating with other countries and territories for assistance, said Dinh Viet Thang, director general of the Civil Aviation Authority of Vietnam (CAAV) at a conference on Wednesday.

Taiwan and South Korea have agreed to grant Vietnamese airlines fifth freedom traffic rights, which would allow them to carry passengers and goods from their territory to a third country.

The CAAV has been recognized by the U.S. as achieving a Category 1 rating, which means it meets the International Civil Aviation Organization’s standards for personnel licensing, operations and airworthiness.

Technical capability is still an issue for Vietnamese carriers since to operate flights to the U.S. they would need long-haul aircraft.

They would need to meet the ETOPS-180 standard for operating twin-engine aircraft across oceans, which requires them to fly for 180 minutes on just one engine. In the country, only Vietnam Airlines has achieved this standard.

Carriers seeking to fly to the U.S. must get approval from aviation authorities there. Their airports of origin in Vietnam must also be certified by U.S. aviation authorities as meeting their safety standards.

"The U.S. is currently a market with relatively fierce competition," Thang said.

Duong Tri Thanh, general director of Vietnam Airlines, listed a number of difficulties for airlines seeking to fly directly to the U.S.

As of now, there is no commercial aircraft that is capable of effectively carrying out this flight, because the bigger Boeing 777X and Airbus A350-1000 aircraft will not come out until 2022, he said.

The aircraft currently being used, Boeing 787 and Airbus A350, have limited seats and won’t be cost effective, he added.

Since a direct flight from HCMC to Los Angeles would take around 18 hours while a connecting flight with a stopover in Taiwan would take about 22 hours, it would be difficult to attract passengers with the former option, he said.

Direct flights would appeal mostly to business-class passengers, but the current number of business-class passengers is not enough to make the flights profitable, he added.

All Southeast Asian countries tried to operate direct flights to the U.S., but only Singapore Airlines and the Philippines Airlines could sustain them, while most others have switched to connecting flights, he said.

"The mission of going first to lead the way is very important. We will be determined and make careful preparations so that direct flights to the U.S. would soon be a reality."

Bamboo Airways too plans to start direct flights to the U.S. in 2020.

The number of tourists coming to Vietnam from the U.S. grew by 11.9 percent last year from 2017 to 687,000, according to the Ministry of Culture, Sports and Tourism.

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