Thai Vietjet Air JSC Limited, operating as Thai VietJet Air or Vietjet Air Thailand, is a low-cost airline of Thailand and an associate company of Vietnamese VietJet Air (เวียดเจ็ทแอร์).

Vietjet Aviation Joint Stock Company, operating as VietJet Air or Vietjet, is a Vietnamese low-cost airline based in Hanoi. It was the first privately owned airline to be established in Vietnam, being granted its initial approval to operate by the Vietnamese Minister of Finance in November 2007. As of its launch in December 2011, it became the second private airline to offer domestic service in Vietnam, as well as the fifth airline overall to offer civil domestic flights. VietJet Air is owned by Sovico Holdings, HDBank, other organisational investors, and individual stakeholders.