Seattle-based modification specialist Aviation Partners intends to defend its technology after facing legal action from Airbus centred on its blended winglets.
The move follows Airbus's starting test flights with an A320 fitted with blended 'sharklet' wing-tips.
While Airbus declines to discuss the reasons for its action, Flight International understands that the airframer is seeking to protect intellectual property and design.
The two sides have previously co-operated on the technology, with Airbus having flown Aviation Partners' blended winglets on an A320 in Toulouse as well as a JetBlue Airways A320.
Aviation Partners chief Joe Clark said he is "surprised" at the lawsuit which intends to "invalidate our patent" on blended winglets, particularly given the long-running efforts to work with the airframer.
"We have had many meetings with their engineering group and top executives, both in America and Europe," he said, adding that the demonstration flights have achieved "excellent results".
"We will vigorously protect our patented technology and intellectual property, which is currently saving the world billions of gallons of fuel," said Clark.
"This is all about efficiency. We want to get our blended winglet technology on as many airplanes as possible to save as much fuel as possible."