Bombardier has said it needs to make more efficiency savings in Northern Ireland.
The news will be met with concern among its 4,000 workers in Belfast, following several redundancy programmes in recent years.
Its boss of aerostructures, Michael Ryan, said it is under pressure to make 20% savings on wings made in Belfast for Airbus.
Airbus wants to increase sales of the A220 plane by making it cheaper.
The A220 is the renamed Bombardier CSeries, in which Airbus recently acquired a majority stake.
Speaking at the Farnborough Air Show, Mr Ryan said: "Airbus are going to be challenging all suppliers for cost reductions of 20%.
"How do we do that? Part of it will be in our overheads. Part of it is efficiencies as well."
Asked about job cuts, he said he would "never rule out any scenario".
However, he added that the outlook for Bombardier in Northern Ireland "is much more positive than it was".
Airbus currently makes wings for most of its other aircraft in Wales.
Mr Ryan doubted Airbus would shift wing making for the A220 from Belfast.
"Anybody who wants to do that is taking a risk," he said.
"My challenge to all our employees is to make moving the wings as much impossible to do as it would be possible to do."
But the Airbus tie-up on what is now the A220 is likely to increase sluggish sales.
Last week, Airbus announced a major order from US carrier JetBlue.