Refer to the input text as context and select the correct relationship between 'Airbus' and 'aircraft' from the available options.
Options: product/material produced, developer, position held, employer

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