What Frontier Group Holdings, Inc. told the SEC could break it.

Aircraft fuel is one of Frontier's largest costs — approximately 24% of total operating expenses in 2025 (28% in 2024 and 31% in 2023) — and is priced mainly off Gulf Coast jet fuel/U.S. Gulf Coast indices; jet-fuel and crude-oil prices are volatile due to global, geopolitical and supply factors, and because Frontier sells many tickets well in advance it may be unable to raise fares quickly enough to offset rapid fuel-price increases, materially affecting results.

“Aircraft fuel represented approximately 24 %, 28 % and 31 % of total operating expenses for the years ended December 31, 2025, 2024 and 2023, respectively. Gulf Coast Jet and U.S. Gulf Coast indexed fuel are the Company's basis for the majority of aircraft fuel purchases.”

Frontier is exposed to trade and aviation regulation: U.S. tariffs on EU imports (a 10%–15% tariff on new commercial Airbus aircraft) apply to aircraft it is already contractually obligated to purchase and could raise fleet costs, and new/increased tariffs on foreign-sourced aircraft and parts could materially increase its costs; it also faces FAA/DOT actions (e.g., a temporary 10% flight reduction at 40 major airports announced November 2025 amid the government shutdown), potential restrictions on airline loyalty programs (FRONTIER Miles), and sustainable-aviation-fuel/CORSIA emissions requirements.

“the United States imposed these tariffs on certain imports from the European Union, including a 10% tariff on new commercial aircraft. In February 2020, the United States announced an increase to this tariff from 10% to 15%. These tariffs apply to aircraft that we are already contractually obligated to purchase.”

Frontier's cost strategy of operating a single-family Airbus A320 fleet creates supplier dependence: it relies on a sole-source supplier, Airbus, for all of its aircraft and on only two suppliers (including CFM International) for its engines, and its long-term fleet and order book commit it to Airbus aircraft for years; manufacturing defects, delivery delays, spare-part shortages, groundings or other disruptions at Airbus or its engine makers could materially impair its fleet growth and operations with no readily available alternative.

“We depend on a sole-source supplier for our aircraft and two suppliers for our engines.”

Frontier funds its fleet and operations with substantial secured financing: in 2025 it issued ~$105 million of enhanced equipment trust certificates (2025-1 EETCs) secured by liens on substantially all of its spare parts and tooling, generated $441 million of cash from aircraft/engine sale-leasebacks, and amended its Revolving Loan Facility to $220 million of commitments, ending 2025 with $874 million of total liquidity ($654M cash plus revolver availability); as a capital-intensive carrier it depends on continued access to debt, sale-leaseback and capital markets, so financing-market disruption or rising rates would pressure liquidity.

“We issued approximately $105 million of class A-1 enhanced equipment trust certificates (“2025-1 EETCs”), which are secured by liens on substantially all of our spare parts and tooling.”