Lack of air tickets during holidays

All domestic flights between big cities during the upcoming Liberation Day (April 30th) and Labour Day (May 1st) holidays are fully booked while prices of other means of transport have increased.
According to booking offices of Vietnam Airlines and Jetstar Pacific, economy tickets for flights between big cities such as Hanoi, HCMC, Hue, Danang, Nha Trang, Quy Nhon, Da Lat, Phu Quoc and others, have been booked out between April 27th and 30th.
Most of passengers are tourists who take tours upcoming Liberation Day (April 30th) and Labour Day (May 1st) holidays.
The same situation has been seen in international flights to Singapore, Thailand and Malaysia during these events.
According to representatives of these booking offices, many tourists failed to get air tickets as they had not planned for their holidays in advance.