IAG has used Aer Lingus slots at Heathrow as security against a near $1.8bn revolving credit facility which the airline group has secured to prop up its finances.
IAG said it has arranged the new revolving credit facility (RCF) with a syndicate of banks.
The facility is available to Aer Lingus, British Airways and Iberia, each of whom has a separate borrower limit within the overall facility.
IAG did not provide a breakdown of how much is available to each carrier.
The money available under the revolving credit facility will be available for a period of three years, with two one-year extensions possible at the discretion of lenders.