|Photo Credit: VietJet Air|
In September, VietJetAir and Airbus agreed a provisional order for the mostly A320 planes, but the deal did not show up in the order book of Airbus in its 2013 data.
"They are very close to a deal and this will be one of the big orders at the airshow," said one source.
A firm order is seen as a strong indication of future revenue for airplane manufacturers and triggers a deposit from airlines. Airlines mainly pay for aircraft when they take delivery and usually win significant discounts for large orders.
The latest deal worth $9 billion at list prices, includes firm orders for 62 medium-haul jets as well as options for 30 more. The sources spoke on condition of anonymity as the matter is not public.
VietJetAir company officials could not be reached by Reuters on Tuesday, the start of the new year holidays in the country.
An Airbus spokesman in Singapore said: "We don't comment on discussions that may or may not be taking place with customers or reports of potential announcements."