LONG-TERM DEBT

Long-term debt obligations (in millions):



	2017			2016
Fixed-rate notes payable due through 2028	$	959		$	1,179
Variable-rate notes payable due through 2028	1,625			1,803
Less debt issuance costs	(15		)	(18		)
Total debt	2,569			2,964
Less current portion	307			319
Long-term debt, less current portion	$	2,262		$	2,645

Weighted-average fixed-interest rate	4.2		%	4.4		%
Weighted-average variable-interest rate	2.8		%	2.4		%

During 2017, the Company's total debt decreased $395 million, primarily due to payments of $397 million in 2017, including the prepayment of $74 million of debt. Approximately $2.2 billion of the loans are secured by a total of 113 aircraft and two spare engines. An additional $392 million is secured by Air Group's interest in certain aircraft purchase deposits.

The Company's variable-rate debt bears interest at a floating rate per annum equal to a margin plus the three or six-month LIBOR in effect at the commencement of each semi-annual or three-month period, as applicable. As of December 31, 2017, none of the Company's borrowings were restricted by financial covenants.

Long-term debt principal payments for the next five years and thereafter (in millions):



	Total
2018	$	310
2019	393
2020	449
2021	414
2022	247
Thereafter	768
Total principal payments	$	2,581

Bank Line of Credit

The Company has three credit facilities with availability totaling $475 million. All three facilities have variable interest rates based on LIBOR plus a specified margin. One credit facility increased from $100 million to $250 million in June 2017. It expires in June 2021 and is secured by aircraft. A second credit facility increased from $52 million to $75 million in September 2017. It expires in September 2018, has a mechanism for annual renewal, and is secured by aircraft. A third credit facility increased from $100 million to $150 million in March 2017. It expires in March 2022 and is secured by certain accounts receivable, spare engines, spare parts and ground service equipment. The Company has secured letters of credit against the $75 million facility, but has no plans to borrow using either of the two other facilities. All three credit facilities have a requirement to maintain a minimum unrestricted cash and marketable securities balance of $500 million. The Company was in compliance with this covenant at December 31, 2017.