DALLAS — Southwest Airlines Co. said Monday that it borrowed $600 million from Citibank and seven European banks to bolster its cash position because of uncertainty about the economy.

The airline disclosed in a regulatory filing that it had tapped the full amount of the loans on Friday.


The loans were secured by the first-lien mortgages on 21 of Southwest's Boeing 737-700 aircraft.

The filing didn't give a purpose for the debt, but spokeswoman Beth Harbin said, "It's due to uncertainty about the economy and the credit market and the high price of fuel."