Utilize the input text as a context reference, choose the right relationship between Aer Lingus and Dublin from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

Adding Aer Lingus to its portfolio of airlines - British Airways, Iberia and Spanish budget carrier Vueling - opens a new avenue of growth for IAG, allowing it to expand capacity on lucrative transatlantic routes by using Dublin Airport.

Answer: location_of_formation