⚠ One Aircraft, One CustomerLow threat

RTX (RTX) — threat to the moat

The F135 has no competitor, but it has one aircraft and one lead customer, and each annual production lot moves Pratt & Whitney's numbers.

The F135's strength is also its concentration. It has one application, the F-35, and one ultimate customer base of governments, led by the United States. RTX sold $33,279 million to the U.S. government in 2025, 38% of net sales1, and the F135 is one of its largest lines inside Pratt & Whitney.

Sales to the U.S. government, share of RTX net sales (%)46%202340%202438%2025RTX Form 10-K FY2025
Falling as commercial sales grow.

A programme this size is a political object. Production lots are awarded annually, and the timing moves the numbers: the 23% rise in military engine sales in the second quarter of 2026 benefited from the Lot 18 award received a year earlier2. A delayed lot, or a cut in annual buys, lands directly on the segment.

The company's own risk factors flag defence contracting risks, including the Department of War's use of other transaction agreements and bid protests3, which can shift how programmes are bought.

The programme's sustainment is where RTX's exposure will sit for the longest. Pratt & Whitney booked $2.4 billion of F135 sustainment work in 2025 against $2.9 billion of production4. If production lots taper, sustainment would become the larger stream, and it depends on how many F-35s the U.S. and its allies keep flying rather than on how many they buy.

The measure of this risk is Pratt & Whitney's military sales. They rose 23% in the latest quarter5; two consecutive years of decline in a budget that the government has asked to raise by about 25% would say the F-35 has passed its peak.

References
  1. ReportedRTX sold $33,279 million to the U.S. government in 2025, 38% of net sales, and the F135 is one of its largest lines inside Pratt & Whitney.
    RTX Form 10-K for fiscal 2025 - customers and backlog: sales to the U.S. government (38%, 40%, 46% of net sales in 2025-2023), Airbus (about 14%, 14%, 17% before discounts and incentives; 29%, 31%, 48% of Pratt & Whitney sales), Boeing and Airbus at 16% of Collins sales, international sales of 47%, and total, commercial and defence backlog with remaining performance obligations. — FY2023-FY2025 · publ. 6 February 2026 · source ↗
  2. ReportedProduction lots are awarded annually, and the timing moves the numbers: the 23% rise in military engine sales in the second quarter of 2026 benefited from the Lot 18 award received a year earlier.
    RTX second-quarter 2026 earnings call transcript (The Motley Fool) - Raytheon bookings and book-to-bill, GTF aircraft-on-ground and MRO output, munitions output, framework agreements, the defence budget request, GTF Advantage, Collins margin plans and segment outlook - defence: Raytheon bookings, book-to-bill and backlog, munitions output, framework agreements and the budget request. — Q2 2026 · publ. 24 July 2026 · source ↗
  3. ReportedThe company's own risk factors flag defence contracting risks, including the Department of War's use of other transaction agreements and bid protests, which can shift how programmes are bought.
    RTX Form 10-K for fiscal 2025 - Item 1A risk factors: competition on price, delivery and technology; customers buying parts from suppliers other than the original equipment manufacturer; discounts and guarantees to win engine positions; new defence entrants; GTF durability; reputational harm; pension sensitivity to the discount rate; tariffs. — FY2025 · publ. 6 February 2026 · source ↗
  4. ReportedPratt & Whitney booked $2.4 billion of F135 sustainment work in 2025 against $2.9 billion of production.
    RTX Form 10-K for fiscal 2025 - customers and backlog: sales to the U.S. government (38%, 40%, 46% of net sales in 2025-2023), Airbus (about 14%, 14%, 17% before discounts and incentives; 29%, 31%, 48% of Pratt & Whitney sales), Boeing and Airbus at 16% of Collins sales, international sales of 47%, and total, commercial and defence backlog with remaining performance obligations. — FY2023-FY2025 · publ. 6 February 2026 · source ↗
  5. ReportedThey rose 23% in the latest quarter; two consecutive years of decline in a budget that the government has asked to raise by about 25% would say the F-35 has passed its peak.
    RTX second-quarter 2026 earnings call transcript (The Motley Fool) - Raytheon bookings and book-to-bill, GTF aircraft-on-ground and MRO output, munitions output, framework agreements, the defence budget request, GTF Advantage, Collins margin plans and segment outlook - defence: Raytheon bookings, book-to-bill and backlog, munitions output, framework agreements and the budget request. — Q2 2026 · publ. 24 July 2026 · source ↗
Sources
Generated September 28, 2026