Long-Term Debt

As of March 31, 2016, the Company has issued non-public and public debt instruments. The Company's indebtedness includes the 2014 Framework Agreement, the 2015 Facility Agreements and the 2015-1 EETCs, as defined in the Company's Form 10-K for the year ended December 31, 2015.

2015-1 EETCs

In August 2015, the Company created two separate pass-through trusts, which issued approximately $576.6 million aggregate face amount of Series 2015-1 Class A and Class B enhanced equipment trust certificates (EETCs) in connection with the financing of 15 aircraft. Each class of certificates represents a fractional undivided interest in the respective pass-through trusts and is not an obligation of the Company. The proceeds from the issuance of these certificates are initially held in escrow by a depositary and, upon satisfaction of certain terms and conditions, are released and used to purchase equipment notes which are issued by the Company and secured by the Company's aircraft. As of March 31, 2016, $194.7 million of the proceeds from the sale of the 2015-1 EETCs had been used to purchase equipment notes in connection with the financing of one Airbus A320 aircraft and four Airbus A321 aircraft. On March 31, 2016, the Company took delivery of two aircraft for which escrowed proceeds in the amount of $73.4 million were used to purchase equipment notes in April 2016. For further discussion of these two March 2016 aircraft deliveries, refer to Note 10, Subsequent Events. The remaining eight aircraft are scheduled for delivery between April 2016 and December 2016.

The Company evaluated whether the pass-through trusts formed are variable interest entities (VIEs) required to be consolidated by the Company under applicable accounting guidance. The Company determined that the pass-through trusts are VIEs and that it does not have a variable interest in the pass-through trusts. Based on this analysis, the Company determined that it is not required to consolidate these pass-through trusts.

Long-term debt is comprised of the following:



	As of				Three Months Ended March 31,
	March 31, 2016		December 31, 2015		2016		2015
	(in millions)				(weighted-average interest rates)
Fixed-rate senior term loans due through 2027	$	476.2	$	484.2	4.10	%	4.10	%
Fixed-rate junior term loans due through 2022	52.6		54.3		6.90	%	6.89	%
Fixed-rate class A enhanced equipment trust certificates due through 2028	154.2		95.8		4.03	%	N/A
Fixed-rate class B enhanced equipment trust certificates due through 2024	40.5		25.0		4.37	%	N/A
Long-term debt	$	723.5	$	659.3
Less current maturities	53.0		49.6
Less unamortized discounts, net	15.4		13.0
Total	$	655.1	$	596.7

During the three months ended March 31, 2016 and 2015, the Company made scheduled principal payments of $9.7 million and $2.6 million on its outstanding debt obligations, respectively.

At March 31, 2016, long-term debt principal payments for the next five years and thereafter are as follows:



	March 31, 2016
	(in millions)
remainder of 2016	$	45.0
2017	55.2
2018	58.4
2019	59.1
2020	59.2
2021 and thereafter	446.6
Total debt principal payments	$	723.5

Interest Expense

Interest expense related to long-term debt consists of the following:



	Three Months Ended March 31
	2016		2015
	(in thousands)
Senior term loans	$	5,048	$	2,194
Junior term loans	937		419
Class A enhanced equipment trust certificates	1,183		—
Class B enhanced equipment trust certificates	336		—
Commitment fees	35		—
Amortization of debt discounts	516		159
Total	$	8,055	$	2,772