Qantas's low-cost arm Jetstar is looking to place a sizeable follow-on order for Airbus A320-family aircraft.
The Australian carrier says it is looking to place additional orders for delivery from 2009, when the last of nine A320s already on order are delivered.
An evaluation is under way to determine how many additional aircraft may be required, after which Qantas board approval will be sought.
"We are looking at putting together a solid business case around a very large order for A320s," says the airline, which adds that it may also consider adding larger A321s.
"We are very serious about this. We see some great growth opportunities within Australia and as our pan-Asia operations ramp up."
Additional aircraft would primarily be for the main domestic operation within Australia, but some could be operated by Singapore-based associate Jetstar Asia.
Pacific Airlines of Vietnam - in which Qantas is taking a 30% stake and which is expected to be rebranded Jetstar next year - could also take some.
Jetstar operates 24 A320s, operated mainly within Australia but also serving New Zealand and Singapore.
Earlier this year Qantas ordered nine additional A320s for Jetstar, which is facing new competition at home from growing Virgin Blue as well as Singapore-based Tiger Airways, which is establishing an Australian domestic subsidiary.