Aviation authorities said this was being done in order to reduce congestion at the Noi Bai and Tan Son Nhat international airports that have both closed off a runway for major repairs, leaving just one in use.

Specifically, there would be a maximum of eight flights landing or taking off at Tan Son Nhat every 15 minutes and seven in Noi Bai, according to the Civil Aviation Authority of Vietnam (CAAV).

The shorter time blocks will allow aircraft less time to linger in parking bays and free up space for rotation, allowing more frequency and less congestion.

The CAAV also said there would be only one plane allowed to land or take off every five minutes for the Hanoi-HCMC route and vice versa.

Over the past two weeks, the two airports have determined their flight frequencies in one-hour blocks, with a maximum of 32 flights per hour for Tan Son Nhat and 27 for Noi Bai.

Airport authorities would monitor airlines’ flight schedules and would cancel flights if they failed to comply with the latest adjustment.

Several carriers and passengers have complained about a rash of delayed flights at both airports of late.

Last week, the Ministry of Transport asked the CAAV to instruct airlines to temporarily divert some of their flights to airports near Hanoi and HCMC instead, for example the Cat Bi airport in Hai Phong City, Tho Xuan airport in Thanh Hoa Province, Can Tho airport in Can Tho City and Cam Ranh airport in Nha Trang Town in order to reduce congestion.