From Hanoi, there are international flights on Thai Airways International to Chiang Mai:

From		To		Transit	Flight
City	Local time	City	Local time	BangKok	TG695
Hanoi	18:10	Chiang Mai	23:40

* Flight time and schedules may change, please check on actual date for the update.

See Also:

Return flight

Flights from Chiang Mai to Hanoi

Other flights from Hanoi to Thailand

Flights from Hanoi to Bangkok
Flights from Hanoi to Phuket

International flights from Ho Chi Minh City to Thailand

Flights from HoChiminh to Bang Kok
Flights from HoChi Minh City to Chiang Mai
Flights from HoChi Minh City to Phuket