Airbus's chief salesman is hoping for a decision shortly in favour of increasing production capability for the A350-1000.
The largest member of the A350 family, due to enter service in 2017, has secured orders totalling 110 aircraft following a pick-up from customers over the past year.
Singapore Airlines became the latest to express interest in the type following its decision to take a further 30 A350-900s, which it is able to convert to the -1000 if required.
Airbus chief operating officer for customers John Leahy says he would like to see a decision soon on raising the rate of production for the -1000.
"I could sell quite a few more if I had early delivery slots," he says.
Singapore Airlines' fleet decision, he adds, shows that the A350-900 is capable of competing with the proposed 787-10X - a double-stretched aircraft, Leahy notes.
He reiterates that Airbus does not intend to stretch the A350 further, claiming that a double-stretch simply results in loss of range and inadequate thrust.
Boeing has just started final assembly of the 787-9, among the customers for which is Singapore Airlines with an order for 20.
Leahy scorns Boeing's efforts to revamp the 777 as the 777X, insisting that the airframer is developing the aircraft because it is "worried" about the A350-1000.
"Folding wings," he says, referring to one of the proposed features of the 777X. "That's never going to happen."