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.
Refer to the input text as context and select the correct relationship between 'Aer Lingus' and 'Dublin' from the available options.
Options: parent organization, platform, location of formation, original broadcaster