DENVER INTERNATIONAL AIRPORT]

Exhibit 10.1(d)

[DENVER INTERNATIONAL AIRPORT]

May 5, 2015

Frontier Airlines, Inc.

Attn: Xxxxx Xxxxxxx

0000 Xxxxx Xxxx

Xxxxxx, XX 00000

Dear Xx. Xxxxxxx,

This Letter of Agreement summarizes the essential business terms by which the City and County of Denver, on behalf of its Department of Aviation, will permit Frontier Airlines, Inc. (“Frontier”) to reconfigure its leasehold at Denver International Airport (“DEN”).

On June 9, 2014, Frontier and the City entered into an Airport Use and Lease Agreement (the “Agreement”), which will expire on December 31, 2016. In February 2015, Frontier and DEN staff began discussions concerning the possible reconfiguration of the Demised Premises described in the Agreement in order to better align Frontier’s leasehold with its current service schedule. Based on these discussions, the parties have agreed to the following business terms:

1. Frontier will release between 20,500 and 21,500 square feet of specifically identified signatory and non-signatory space.

2. Frontier will release preferential gates X00, X00, X00, X00, X00, X00, X00, and A30.

3. Frontier will retain or expand to gates A32, A34, A36, A38, A40, A42, A44 and A46 as preferential gates.

4. The City will work with Spirit Airlines to relocate Spirit from gate A44 to another location. In addition, the City will vacate its Radio Shop for Frontier to occupy.

5. Frontier will reimburse the City for the costs incurred in order to complete the actions listed in Paragraph 4. These costs shall not exceed $***** and will be applied towards the procurement and installation of comparable common use technology which currently exists at A44 and A46. Frontier agrees to reimburse the City for this work within thirty (30) days upon receipt of invoice based on actual costs.

***** Confidential portions of the material have been omitted and filed separately with the Securities and Exchange Commission.

6. Frontier will have full access to two City common use gates, separate from the gates listed in paragraph 7. Frontier will continue to operate their international arrivals using gates A33, A35 or A37.

7. In light of the anticipated conversion of gates A42 and A44 to international gates in First Quarter 2016, Frontier agrees that they will operate international arrivals out of these gates as a priority. The City agrees to provide City common use gates as overflow for Frontier’s international flights at A33, A35 or A37. For clarification the priority on gates A42 and A44 will be as follows;

1. Frontier Airlines International Arrivals

2. Frontier Airlines Domestic Arrivals

3. Other Airline International Arrivals

8. The transition to the new gates listed in paragraph 3 will take place during the months of May and June 2015 and be completed by July 1, 2015 for gate changes and July 31, 2015 for facility changes.

9. Frontier agrees to coordinate regularly with the City on the sequencing and timing of the transition in order to meet the deadlines set out in paragraph 8 above.

10. File Agreement will be amended to reflect these accommodations. The parties intend for the Agreement amendment to be effective on July 1, 2015 and to continue in effect through the remaining term of the Agreement (December 31, 2016), The parties agree to work cooperatively to accomplish the required amendments.

11. This Letter of Agreement will be in full force and effect on July 1, 2015. Any changes to this Letter of Agreement will require the consent of both Frontier and DEN. All terms and conditions are subject to the review and confirmation of Denver City Council through amendment to the Use and Lease Agreement. Notwithstanding the above, the City shall exercise reasonable business efforts to implement the paragraph 4 gate relocations prior to July 1, 2015.

12. Both parties will use best efforts to sign an amendment to the Agreement in advance of July 1, 2015 however the parties acknowledge that the reduction in rent payable will be adjusted in line with the gate and other space changes from July 1, 2015.

13. All airport related revenue sharing/concession credit will be payable pro-rata on the basis of space used in the airport during the period of January 1, 2015 to June 30, 2015 and thereafter from July 1, 2015 for the remainder of the lease term.

14. All space changes are set out in Schedule A (attached) of this Letter of Agreement.

The City will have to commit considerable staff resources, undertake extensive planning, expend costs, and coordinate with other airlines to accommodate and support the reconfiguration of Frontier’s leasehold. To initiate this effort, the City requires certainty that Frontier agrees with the essential business terms enumerated above. For this reason, the City has reduced the deal points to writing and is requesting Frontier’s approval of this Letter of Agreement on or before May 5, 2015.

Frontier, by signing and returning this letter agreement to DEN, affirms that they have read the terms listed above and agree to the terms and conditions contained herein.

The City is committed to retaining Frontier as our hometown airline and hopes that the reconfiguration of Frontier’s leasehold will support your continued presence at DEN for many years to come,

Sincerely,

/s/ Xxx Day				/s/ Xxxxx Xxxxxxx
Xxx Day				Xxxxx Xxxxxxx,
Chief Executive Officer				Chief Financial Officer
Denver International Airport				Frontier Airlines

Attached: Schedule A

SCHEDULE A

Current Space

Tenant Finish

Sq. Ft.

Return Y/N or New

After Changes

Tenant Finish

Sq. Ft.

Ticket Counter

Ticket Counter

R16-2-6-E6-N27-1

Yes

1070.30

No

R16-2-6-E6-N27-1

Yes

1070.30

Ticket Office

Ticket Office

R16-1-6-E3-N24-3

Yes

1233.60

No

R16-1-6-E3-N24-3

Yes

1233.60

Baggage Service Office

Baggage Service Office

R16-1-4-E4-N23-1

Yes

300.00

No

R16-1-4-E4-N23-1

Yes

300.00

R16-1-5-E3-N24-1

Yes

460.6

No

R16-1-5-E3-N24-1

Yes

460.60

Terminal Total

3064.50

Terminal Total

3064.50

Hold Rooms

Hold Rooms

New

R17-2-3-E16-S4-1 - A46

Yes

1988.10

New

R17-2-3-E11-S4-1 - A44

Yes

2141.00

R17-2-3-E8-S4-1 - A42

Yes

2143.50

No

R17-2-3-E8-S4-1 - A42

Yes

2143.50

R17-2-3-E5-S4-1-A40

Yes

1997.50

No

R17-2-3-E5-S4-1 - A40

Yes

1997.50

R17-2-3-W11-S4-1 -A38

Yes

1907.70

No

R17-2-3-W11-S4-1 - A38

Yes

1907.70

R17-2-3-W18-S4-1 - A34/A36

Yes

3907.80

No

R17-2-3-W18-S4-1 - A34/A36

Yes

3907.80

R17-2-3-W23-S4-1 - A32

Yes

1925.30

No

R17-2-3-W23-S4-1 - A32

Yes

1925.30

R17-2-3-W26-S4-1 - A30

Yes

1874.00

Yes

R17-2-3-W28-S4-1 - A28

Yes

2059.70

Yes

R17-2-3-W28-N1-1 - A27/A31

Yes

5989.00

Yes

Hold Room Total

21804.50

Hold Room Total

16010.90

Ramp Aircraft Parking(Ln. Ft.)

2086.50

Ramp Aircraft Parking (Ln. Ft.)

1138.40

Office Space

Office Space

R17-2-3-W10-S4-1

Yes

2386.50

Yes

R17-2-3-W13-S4-3

Yes

373.80

No

R17-2-3-W13-S4-3

Yes

373.80

R17-2-3-W13-S4-1

Yes

1058.50

No

R17-2-3-W13-S4-1

Yes

1058.50

R17-2-4-W20-S5-1

Yes

2369.70

Yes

R17-2-4-W20-N1-1

Yes

1082.30

Yes

R17-2-4-E19-S3-2

Yes

130.30

No

R17-2-4-E19-S3-2

Yes

130.30

R17-2-9-W0-S9-1

Yes

309.60

Yes

R17-2-9-W0-S9-4

Yes

58.80

Yes

New

R17-2-4-E18-S5-1

Yes

1253.70

New

R17-2-4-E18-N2-5

Yes

170.00

New

R17-2-4-E21-N2-2

Yes

603.70

Total Office Space

7769.50

Total Office Space

3590.00

Operations Space

Tenant Finish

Current Exhibits

R17-2-2-W27-N5-2

Yes

85.00

Yes

R17-2-2-W27-S5-2

Yes

85.00

Yes

R17-2-2-W24-S3-1

No

1778.40

Yes

R17-2-2-W22-N1-3

Yes

1084.60

Yes

R17-2-2-W23-S4-1

Yes

563.40

Yes

R17-2-2-W23-S2-1

Yes

559.10

Yes

R17-2-2-W22-NO-2

Yes

188.80

Yes

R17-2-2-W23-S4-2

Yes

484.20

Yes

R17-2-2-W13-S4-1

No

776.70

Yes

R17-2-2-W13-S5-2

Yes

83.30

Yes

R17-2-2-E2-S7-1

Yes

420.60

No

R17-2-2-E2-S7-1

Yes

420.60

R17-2-2-E5-S2-4

Yes

240.10

Yes

R17-2-1-W28-S3-2

Yes

148.20

Yes

New

R17-2-2-E8-S5-1

Yes

84.99

New

R17-2-2-E11-S4-2

Yes

4300.00

New

R17-2-2-E12-S4-2

No

782.70

Total Operations

6497.40

Total Operations

5588.29

May 1, 2015

Current Space

Tenant Finish

Sq. Ft.

Return Y/N or New

After Changes

Tenant Finish

Sq. Ft.

Basement Space (Written off space)

R17-2-1-W18-S4-3

No

903.00

Yes

R17-1-1-W11S6-3

No

400.00

Yes

New

Caged Area

No

500.00

Total Basement

1303.00

Total Basement

500.00

May 1, 2015

Current Space		After July Changes
SIGNATORY SPACE - TERMINAL		SIGNATORY SPACE - TERMINAL
Ticket Counter		Ticket Counter
R16-2-6-E6-N27-1		R16-2-6-E6-N27-1
Ticket Office		Ticket Office
R16-1-6-E3-N24-3		R16-1-6-E3-N24-3
Baggage Service Office		Baggage Service Office
R16-1-4-E4-N23-1		R16-1-4-E4-N23-1
R16-1-5-E3-N24-1		R16-1-5-E3-N24-1
SIGNATORY SPACE - CONC A		SIGNATORY SPACE - CONC A
Hold Rooms		Hold Rooms
		R17-2-3-E16-S4-1 - X00
		X00-0-0-X00-X0-0 - X00
X00-0-0-X0-X0-0 - X00		X00-0-0-X0-X0-0 - X00
X00-0-0-X0-X0-0 - X00		X00-0-0-X0-X0-0 - X00
X00-0-0-X00-X0-0-X00		R17-2-3-W11-S4-1 - A38
R17-2-3-W18-S4-1 - A34/A36		X00-0-0-X00-X0-0 - X00/X00
X00-0-0-X00-X0-0 - X00		X00-0-0-X00-X0-0 - A32
R17-2-3-W26-S4-1 - X00
X00-0-0-X00-X0-0 - X00
X00-0-0-X00-X0-0 - X00/X00
Office Space		Office Space
R17-2-3-W10-S4-1
R17-2-3-W13-S4-2
R17-2-3-W13-S4-3
R17-2-3-W13-S4-1
R17-2-4-W20-S5-1
R17-2-4-W20-N1-1
R17-2-4-E19-S3-2		R17-2-4-E19-S3-2
R17-2-9-W0-S9-1
R17-2-9-W0-S9-4
		R17-2-5-W5-N3-2
		R17-2-5-W5-N3-1
		R17-2-5-W4-N5-1
		R17-2-5-W4-N5-2
Operations Space
R17-2-2-W27-N5-2
R17-2-2-W27-S5-2
R17-2-2-W24-S3-1
R17-2-2-W22-N1-3
R17-2-2-W23-S4-1
R17-2-2-W23-S2-1
R17-2-2-W22-N0-2
R17-2-2-W23-S4-2
R17-2-2-W13-S4-1
R17-2-2-W13-S5-2
R17-2-2-E2-S7-1		R17-2-2-E2-S7-1
R17-2-2-E5-S2-4
R17-2-l-W28-S3*2
		R17-2-1-E19-S5-1
		R17-2-2-E11-S4-2
		R17-2-2-E12-S4-2
Basement Space (Written off space)
X00-0-0-X00-X0-0		Xxx Xxxxx Xxxx
X00-0-0-X00X0-0		New Office Area
Total Basement		Total Basement

Current Space		After July Changes
TOTAL SIGNATORY		TOTAL SIGNATORY
Concourse A Non-Signatory
Office
R17-2-3-W7-S4-1
Concourse A Non-Signatory Operations
R17-2-2-W13-S4-1
Terminal Non-Signatory Ticket Counter
R16-1-6-E6-N25-1