Utilize the input text as a context reference, choose the right relationship between 'Airbus' and 'aircraft' from the options.
Options: position held, developer, employer, product/material produced

Boeing has gained invaluable technical knowledge required to design, produce and certify commercial aircraft and operates in what is essentially a market duopoly with rival Airbus for the industry's bread-and-butter single and twin-aisle commercial aircraft segment.
product/material produced