Stockpiling parts to mitigate the impact of a no-deal Brexit would cost Bombardier's Belfast business up to £30m, the plane maker has warned.
Michael Ryan, the head of the firm's Northern Ireland operation warned that spending such a sum to store goods is "not how we can afford to run a business".
Mr Ryan told the Press Association it was "cash that I don't have".
About 4,000 people are employed at Bombardier's Belfast operation.
There are fears the movement of goods could be disrupted by long queues at ports if the UK is unable to reach an agreement with the European Union over Brexit.
Mr Ryan said his Belfast plant operates a "just in time" supply policy to avoid the expense of stocking excess materials.
The company uses hundreds of components which are modified throughout its supply chain, crossing between the UK and the rest of the EU on multiple occasions.
There were 1,755 such shipments in 2016.
Asked about the implications of a no-deal Brexit, Mr Ryan said: "Our customers are expecting of us... the only solution to not having some sort of a deal will be to stockpile parts.
"That will cost us about £25-30m to hold a number of months' worth of material to avoid stopping our lines."
Won't destroy future
The factory makes wings for the Airbus A220, which was known as the CSeries until Airbus took a majority stake in the aircraft programme amid concerns about the plane's feasibility.
Mr Ryan said the firm will begin arrangements to stockpile goods by the end of the year if it believes that will be necessary after Brexit.
The UK is set to leave the EU in March 2019.
He believes such a scenario would be a "short-term issue", adding: "I don't expect it to destroy our future."