Long-Term Debt

As of June 30, 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 June 30, 2016, $421.3 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 three Airbus A320 aircraft and eight Airbus A321 aircraft. The remaining four aircraft are scheduled for delivery between August 2016 and January 2017.

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 June 30,				Six Months Ended June 30,
	June 30, 2016		December 31, 2015		2016		2015		2016		2015
	(in millions)				(weighted-average interest rates)
Fixed-rate senior term loans due through 2027	$	468.2	$	484.2	4.10	%	4.04	%	4.10	%	4.04	%
Fixed-rate junior term loans due through 2022	50.7		54.3		6.90	%	6.89	%	6.90	%	6.89	%
Fixed-rate class A enhanced equipment trust certificates due through 2028	333.3		95.8		4.03	%	N/A		4.03	%	N/A
Fixed-rate class B enhanced equipment trust certificates due through 2024	88.1		25.0		4.38	%	N/A		4.38	%	N/A
Long-term debt	$	940.3	$	659.3
Less current maturities	78.6		49.6
Less unamortized discounts, net	25.3		13.0
Total	$	836.4	$	596.7

During the six months ended June 30, 2016 and 2015, the Company made scheduled principal payments of $19.6 million and $8.2 million on its outstanding debt obligations, respectively.

At June 30, 2016, long-term debt principal payments for the next five years and thereafter were as follows:



	June 30, 2016
	(in millions)
remainder of 2016	$	44.7
2017	75.6
2018	74.9
2019	74.1
2020	72.6
2021 and thereafter	598.4
Total debt principal payments	$	940.3

Interest Expense

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



	Three Months Ended June 30				Six Months Ended June 30,
	2016		2015		2016		2015
	(in thousands)
Senior term loans	$	4,964	$	3,426	$	10,012	$	5,620
Junior term loans	905		678		1,842		1,097
Class A enhanced equipment trust certificates	2,698		—		3,881		—
Class B enhanced equipment trust certificates	773		—		1,109		—
Commitment fees	30		—		65		—
Amortization of debt discounts	794		230		1,310		389
Total	$	10,164	$	4,334	$	18,219	$	7,106