The company Airbus, which employs thousands at its wing-making plant in Broughton, Flintshire, is calling for a "lengthy" transition period during Brexit.
It says it needs the time to invest in customs arrangements like electronic border management systems because it needs to move staff and equipment "within hours" around the EU.
The company says it could be put at a "competitive disadvantage" if the UK and EU do not agree on the terms of a transitional deal as soon as possible.
Airbus says UK jobs could be put at risk if British workers are burdened with new visa requirements after Brexit, or if Britain does not secure access to certain research programmes in the event of "no deal".
The national trade association for the sector, ADS Group said increased customs checks could result in £1.5 billion added costs.