The flight route connecting Vietnam’s two largest cities, which takes around two hours, has nearly 893,000 seats scheduled for November, while the route between South Korean capital Seoul and Jeju Island has 1.3 million.

The route between Chinese capital Beijing and Shanghai’s Hongqiao Airport is third with 768,184 seats, followed by the two routes in Japan –Sapporo-Tokyo Hanenda and Fukuoka-Tokyo Hanenda.

Of the top 10 busiest domestic routes in November, China and Japan have four each.

"International flights have felt the impact most acutely due to border controls and mandatory quarantine requirements, domestic routes are starting to recover as people are generally able to move more freely within their countries," OAG said.

Asia is a standout, home to all 10 of the world’s busiest domestic routes this month, the company added.

Vietnam has reopened six international flights to mainland China, Japan, South Korea and Taiwan from September 15, followed by Laos, Cambodia from September 22. It had suspended all international routes in March to contain the Covid-19 outbreak in the country.