Its CEO Dang Tat Thanh said Bamboo Airways could not take off since it is going through "the most difficult examination ever."
"Bamboo Airways is currently going through the final stage of a tight examination by authorities before taking off," he told VnExpress, adding that the first flight would now be in mid-January.
The airline aimed to launch the first flight on December 29, after failing to launch services in October as previously planned.
The carrier, owned by conglomerate FLC, received a license last November but is still awaiting an aircraft operator certificate (AOC).
It was established in May last year with a charter capital of VND700 billion ($30 million), which it increased two months later to VND1.3 trillion ($55.68 million).
It has signed deals to buy 24 Airbus A320neo and 20 Boeing B787-9 Dreamliner aircraft worth a total of $8.6 billion. Earlier this month it took delivery of the first aircraft, an Airbus A319 leased from an Irish company.
The airline plans to operate on 100 routes, connecting major cities and travel destinations in Vietnam with the rest of the world.
FLC chairman Trinh Van Quyet said earlier that the first routes could be between Hanoi and Ho Chi Minh City and from the two cities to Quy Nhon.
Vietnam has four other carriers still in operation: Vietnam Airlines, Vietjet Air, Jetstar Pacific, and VASCO.