Qatar Airways is encouraged by the Bombardier CSeries' commencing its test-flight programme but an order will depend on the aircraft's popularity.
The Doha-based carrier has previously been in talks over the type, and chief executive Akbar Al Baker says the carrier remains interested.
"It is not in the water," he says, indicating that a potential order for the type is still a possibility.
But he says an acquisition will be considered only if "large volumes" of the aircraft are produced.
Al Baker states that the carrier wants to ensure that "the programme is sustainable" before any commitment.
Bombardier began test flights with the CSeries in mid-September. The type has secured 177 firm orders.