Exhibit 99.4

 

Exhibit 99.4 Presentation to Spirit January 2025

Frontier’s proposal ensures superior economics, certainty, and speed for Spirit’s stakeholders relative to the Spirit standalone plan Stronger, More Competitive Airline ïƒ~ Transaction with Frontier creates America’s first low-cost carrier with sufficient scale to compete with the Big Fourïƒ~ Complementary networks bring more low fares to more markets and generate meaningful and achievable synergies Challenges with Spirit’s Standalone Plan ïƒ~ Spirit’s plan relies on robust valuation assumptions against a business plan with significant execution risk to generate equity valueïƒ~ Even if the plan is achieved, creditors do not realize a full recovery, and shareholders have zero recoveryïƒ~ Leverage remains high on 2025E EBITDAR (8.9x) Frontier’s Superior Alternative ïƒ~ Even without synergies, Frontier’s plan provides greater creditor recovery while also providing value to shareholdersïƒ~ On a combined basis, significantly lower leverage on 2025E EBITDAR (4.1x)ïƒ~ On a standalone basis, Spirit would need to achieve a valuation meaningfully higher than its plan currently contemplates for its creditors to realize the economics offered in Frontier’s alternativeïƒ~ A combination with Frontier de-risks Spirit’s business transformation plan and positions the combined airline to more effectively compete with the Big Four over the long term A combination with Frontier can proceed quickly, with minimal required due diligence or closing conditions Confidential and proprietary 2 2

($ in millions) Spirit Standalone Restructuring Frontier Proposal Creditor Consideration Exit Secured Notes $840 $400 11.0% Cash / 8.0% Cash + 4.0% PIK Coupon 11.0% Cash / 8.0% Cash + 4.0% PIK (specifics to be discussed) % Ownership 100% of Spirit 19.0% of PF Frontier + Spirit Pro Forma Entity Spirit Frontier + Spirit Revenue (FY26) $5,411 $11,059 EBITDAR (FY26) $1,041 $3,476 (1) Net Debt (2/28/2025) $5,937 $9,356 Net Leverage(2) 8.9x 4.1x Run-Rate Synergies — $600 Equity Value $806 $13,161 (@ 6.5x EBITDAR FY26 per RSA Plan) Total Value to Stakeholders $1,646 $2,901 Recovery %(4) Recovery %(4) Recovery Recovery %(3) (Excl. Synergies) (Incl. Synergies) Senior Secured Notes 95% 106% 141% Convertible Notes 56% 100% 137% Common Stock(5) $0.00 / share $0.80 / share $1.15 / share Notes: Spirit RSA and Frontier Proposal reflect $350mm equity rights offering. Recovery rates for senior secured notes and convertible notes are based on principal value and share of equity rights offering. Recovery rates exclude impact from other secured / priority claims. (1) Figures include $600mm of run-rate synergies. (2) Net leverage reflects net debt as of 02/28/2025 divided by 2025E Pro forma EBITDAR incl. 50% credit for synergies. (3) Reflects Spirit equity ownership split of 76% senior secured noteholders, 24% convertible notes. (4) Illustrative equity ownership split of 65% senior secured noteholders, 30% convertible notes, 5% common stock. (5) Per share figures based on Spirit basic shares outstanding as of November 14, 2024; rounded to the nearest $0.05. Confidential and proprietary 3 3

Compelling Proposal to Acquire Spirit To Create America’s First At-Scale, Low-Cost Competitor to Big Four Creating a Stronger Airline with Long-Term Viability to Compete More Effectively • 5th largest U.S. airline, growing to 100M annual passengers and 400+ aircraft within a few years • Top three carrier in more than half of the top 25 U.S. airports • Meaningfully increases presence in numerous major U.S. markets Offering More Low Fares and Premium Options to Travelers • Provides more low fares to more consumers, enabling billions in savings compared to prices charged by Big Four • Improves frequent flyer and loyalty programs as well as a more diversified product with premium options • Enables more reliable service through operating efficiencies • Enhances travel experience for customers Delivering Value for Financial Stakeholders • Creates compelling financial opportunity for Spirit creditors and shareholders • Provides greater value and recovery relative to Spirit standalone restructuring plan Significant Synergy Potential • Opportunity to participate in upside potential from owning a larger, more competitive airline with estimated synergies of $600M+ Confidential and proprietary 4 4

Stronger Airline with Long-Term Viability to Compete Against Big Four 2023 Available Seat Miles Consumers Win: Low Fares with Premium Options 5th largest U.S. airline, growing to 100M annual passengers and 400+ aircraft within a few yearsïƒ~ Provides more low fares to more consumers, enabling billions in savings compared to Top three carrier in more than half of the top 25 U.S. airports prices charged by Big Four ïƒ~ Improves frequent flyer and loyalty programs as well as a more diversified product with premium options ïƒ~ Enables more reliable service through operating efficiencies ïƒ~ Enhances travel experience for customers Frontier + Spirit Combined Source: Company filings. Confidential and proprietary 5 5

Frontier Proposal creates significantly greater value than Spirit Standalone Restructuring Plan. ($ in millions); FY26 EBITDAR Multiples Spirit Standalone Restructuring Frontier Proposal (Excluding Synergies) As of 02/28/2025, $840mm Exit Secured Notes $400mm Exit Secured Notes; 19.0% Ownership to Spirit Frontier Median(1) RSA Plan Valuation Multiple Valuation Multiple 4.5x 5.5x 6.5x 4.5x 5.5x 6.5x Equity Value -—- $806 Equity Value $3,586 $6,462 $9,274 Exit Secured Notes — $539 $700 Exit Secured Notes $333 $333 $333 Equity Interest -—- $613 Equity Interest $442 $796 $1,142 Secured Sr. Secured Noteholders — $539 $1,313 Secured Sr. Secured Noteholders $775 $1,129 $1,475 . Sr % Recovery — 39% 95% Sr . % Recovery 56% 81% 106% Exit Secured Notes — $89 $140 Exit Secured Notes $67 $67 $67 Equity Interest -—- $194 Equity Interest $206 $371 $532 Convert Convertible Noteholders — $89 $334 Convert Convertible Noteholders $272 $437 $599 % Recovery — 15% 56% % Recovery 45% 73% 100% Net Leverage Frontier Proposal (Incl. $600mm of Synergies) $400mm Exit Secured Notes; 19.0% Ownership to Spirit Net Debt as of 02/28/2025 divided by FY25 EBITDAR 8.9x Valuation Multiple 4.5x 5.5x 6.5x Equity Value $6,286 $9,762 $13,161 Exit Secured Notes $333 $333 $333 Equity Interest $774 $1,202 $1,620 4.1x Secured Sr. Secured Noteholders $1,107 $1,535 $1,954 . Sr % Recovery 80% 111% 141% Exit Secured Notes $67 $67 $67 Equity Interest $361 $560 $755 Convert Convertible Noteholders $427 $627 $822 Spirit Standalone Frontier + Spirit % Recovery 71% 105% 137% Source: Spirit Disclosure Statement (Chapter 11 Plan of Reorganization), filed as of December 18, 2024. Notes: Spirit RSA and Frontier Proposal reflect $350mm equity rights offering. Recovery rates for senior secured notes and convertible notes are based on principal value and share of equity rights offering. Recovery rates exclude impact from other secured / priority claims. (1) Median industry multiple based on Southwest Airlines, JetBlue Airways, Frontier Airlines, Allegiant, and Sun Country Airlines. Confidential and proprietary 6 6

($ in millions) Total Value to Stakeholders (Senior Secured Notes + Convertible Notes + Common Equity) Spirit RSA Frontier Proposal (Excl. Synergies) Frontier Proposal (Incl. Synergies) $2,901 $400mm Exit Secured Notes + 19% Equity Interest in PF $2,585 Frontier + Spirit $2,255 $2,162 $1,925 $1,901 $1,594 $1,628 $1,646 $840mm Exit Secured Notes + $1,355 100% Equity Interest $1,264 $1,149 in Spirit $1,081 $808 Exit Secured Notes Amount: $840mm $629 Negative Equity Value / Debt Impairment -—- $108 4.0x 4.5x 5.0x 5.5x 6.0x 6.5x Valuation Multiple (FY26 EBITDAR) Confidential and proprietary 7 7

• Given extensive diligence conducted to date, Frontier envisions an expedited due diligence process that may be completed in approximately 5-10 days • Key diligence items include: – Sales performance relative to plan – Confirmation of latest Pratt & Whitney agreement providing compensation for 2025 AOGs – Updated 2-year cash flow forecast, inclusive of Chapter 11 costs – Disclosure of any material contract or business changes – Tax considerations, including any Chapter 11 impact to NOLs Confidential and proprietary 8 8