GAO Reports: Catalog (2013-2025)
¶ GAO Reports: Catalog (2013-2025)
Note on cost basis: All USD amounts from US government sources (GAO, CBO, DoD) in this article are expressed in Base Year 2012 Dollars (BY2012$). Adjusted for inflation to 2026, actual values are approximately 40–50% higher.
The U.S. Government Accountability Office (GAO) has published at least one report on the F-35 program annually since 2013. This page lists all identified GAO reports related to the F-35 in chronological order.
Total count: 39 reports (including testimonies before Congress)
¶ 2025
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-25-108104 | F-35 Joint Strike Fighter: DOD Continues to Confront Sustainment Challenges | 2025 | Sustainment challenges persist | High |
| GAO-25-107632 | F-35 Joint Strike Fighter: Actions Needed to Address Late Deliveries and Improve Future Development | September 2025 | All 110 aircraft delivered in 2024 were on average 238 days late, mainly due to TR-3 delays | High: TR-3 delays affect Swiss delivery schedule |
¶ 2024
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-24-107177 | F-35 Joint Strike Fighter: More Actions Needed to Explain Cost Growth and Support Engine Modernization Decision | December 2023 | Block 4 modernization: costs rose from $10.6 billion to $16.5 billion; cooling system issues add $38 billion to life-cycle costs | High |
| GAO-24-106909 | F-35 Joint Strike Fighter: Program Continues to Encounter Production Issues and Modernization Delays | May 2024 | Full-Rate Production reached in March 2024, but delivery delays continue; total program costs over $2 trillion through 2088 | High: May delay Swiss deliveries |
| GAO-24-106703 | F-35 Sustainment: Costs Continue to Rise While Planned Use and Availability Have Decreased | April 2024 | Sustainment cost estimates increased 44% from $1.1 trillion (2018) to $1.58 trillion (2023); availability declining for 5 years | High: Directly relevant to Swiss life-cycle costs |
¶ 2023
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-23-106694 | Tactical Aircraft: Technical, Delivery, and Affordability Challenges | March 2023 | F-35 program over a decade behind schedule and $165 billion over original cost estimates; 50% of 2022 deliveries late | High |
| GAO-23-106098 | F-35 Program: DOD Needs Better Accountability for Global Spare Parts | May 2023 | Approximately one million lost spare parts worth $85 million unaccounted for; only 2% of identified losses since 2018 audited | Medium |
| GAO-23-106047 | F-35 Joint Strike Fighter: More Actions Needed to Explain Cost Growth and Support Engine Modernization | May 2023 | Program $183 billion over cost estimates; Block 4 completion postponed to 2029, costs at $16.5 billion | High |
| GAO-23-105341 | F-35 Aircraft: DOD and Military Services Need to Reassess Future Sustainment Strategy | September 2023 | Fleet mission capable rate only 55% in March 2023, far below program targets | High |
| GAO-23-106375 | F-35 Joint Strike Fighter: Annual Report | 2023 | Annual status report summarizing program challenges | Medium |
¶ 2022
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-22-105995 | F-35 Sustainment: DOD Faces Several Uncertainties and Has Not Met Key Objectives | April 2022 | Mission capable rate declined between FY2020-2021; growing number of grounded F-35s due to engine problems | High |
| GAO-22-105128 | F-35 Joint Strike Fighter: Cost Growth and Schedule Delays Continue | April 2022 | Over 800 aircraft delivered, but over a decade behind schedule and $165 billion over cost estimates | High |
| GAO-22-104678 | F-35 Aircraft: DOD Should Assess and Update Its Engine Sustainment Strategy | 2022 | DOD must review engine sustainment strategy | Medium |
¶ 2021
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-21-105282 | F-35 Joint Strike Fighter: Cost and Schedule Risks in Modernization Program Echo Long-Standing Challenges | July 2021 | Program over 8 years late and $165 billion over expectations; modernization facing similar challenges | High |
| GAO-21-439 | F-35 Sustainment: DOD Needs to Cut Billions in Estimated Costs to Achieve Affordability | April 2021 | Sustainment costs rose from $1.11 trillion to $1.27 trillion; $6 billion funding gap in 2036 alone | High |
| GAO-21-226 | F-35 Joint Strike Fighter: DOD Needs to Update Modernization Schedule and Improve Data on Software Development | March 2021 | Block 4 modernization schedule unrealistic; DOD systematically underestimates software development effort | High |
¶ 2020
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-20-665T | F-35 Sustainment: DOD Needs to Address Key Uncertainties as It Re-Designs the Aircraft's Logistics System | 2020 | Testimony on ALIS redesign challenges and sustainment uncertainties | Medium |
| GAO-20-339 | F-35 Joint Strike Fighter: Actions Needed to Address Manufacturing and Modernization Risks | May 2020 | Modernization costs increased by $1.5 billion (14%) since May 2019 | High |
| GAO-20-316 | Weapon System Sustainment: DOD Needs a Strategy for Re-Designing the F-35's Central Logistics System | March 2020 | ALIS not functioning properly; mission-capable aircraft sometimes grounded by inaccurate data | High: ALIS/ODIN affects Swiss fleet as well |
¶ 2019
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-19-341 | F-35 Joint Strike Fighter: Action Needed to Improve Reliability and Prepare for Modernization Efforts | April 2019 | Block 4 modernization ($10.5 billion) without complete business case; reliability needs improvement | High |
¶ 2018
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-18-321 | F-35 Joint Strike Fighter: Development Is Nearly Complete, but Deficiencies Found in Testing Need to Be Resolved | June 2018 | DOD planned to fix critical deficiencies only after Full-Rate Production decision -- contrary to DOD policy | High |
| GAO-18-75 | F-35 Aircraft Sustainment: DOD Needs to Address Challenges Affecting Readiness and Cost Transparency | October 2017 | Over 250 F-35s in service, but depot repair capacity 6 years behind schedule | Medium |
¶ 2017
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-17-690R | F-35 Joint Strike Fighter: DOD's Proposed Follow-on Modernization Acquisition Strategy | August 2017 | DOD expects an additional $3.9 billion over five years for Block 4 modernization | Medium |
| GAO-17-351 | F-35 Joint Strike Fighter: DOD Needs to Complete Developmental Testing Before Making Significant New Investments | April 2017 | Cascading test delays could cost over $1 billion more than budgeted | Medium |
¶ 2016
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-16-634T | F-35 Joint Strike Fighter: Development of New Capabilities Requires Continued Oversight | 2016 | Testimony on need for oversight in new capability development | Low |
| GAO-16-489T | F-35 Joint Strike Fighter: Preliminary Observations on Program Progress | March 2016 | Testimony with preliminary observations on program status | Low |
| GAO-16-439 | F-35 Sustainment: DOD Needs a Plan to Address Risks Related to Its Central Logistics System | April 2016 | ALIS poses significant risks requiring a comprehensive mitigation plan | Medium |
| GAO-16-390 | F-35 Joint Strike Fighter: Continued Oversight Needed as Program Plans to Begin Development of New Capabilities | April 2016 | At $400 billion in procurement costs, the most expensive DOD program; further oversight needed | Medium |
¶ 2015
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-15-429T | F-35 Joint Strike Fighter: Observations on Program Progress | April 2015 | Structural failure, engine failure, and software challenges delayed test schedule | Low |
| GAO-15-364 | F-35 Joint Strike Fighter: Assessment Needed to Address Affordability Challenges | April 2015 | Unexpected development changes due to structural failure in stress testing, engine failure, and software | Medium |
¶ 2014
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-14-778 | F-35 Sustainment: Need for Affordable Strategy, Greater Attention to Risks, and Improved Cost Estimates | September 2014 | Estimated sustainment costs of $1 trillion require an affordable strategy | Medium |
| GAO-14-322 | F-35 Joint Strike Fighter: Problems Completing Software Testing May Hinder Delivery of Expected Warfighting Capabilities | March 2014 | Software testing delays due to late delivery, limited capabilities, and need for rework | Medium |
¶ 2013
| GAO No. | Title | Date | Key Finding | CH Relevance |
|---|---|---|---|---|
| GAO-13-690T | F-35 Joint Strike Fighter: Restructuring Has Improved the Program, but Affordability Challenges and Other Risks Remain | June 2013 | Testimony: restructuring brought improvements, but affordability remains problematic | Low |
| GAO-13-500T | F-35 Joint Strike Fighter: Program Has Improved in Some Areas, but Affordability Challenges and Other Risks Remain | April 2013 | Testimony: improvements in some areas, but ongoing affordability and risk concerns | Low |
| GAO-13-309 | F-35 Joint Strike Fighter: Current Outlook Is Improved, but Long-Term Affordability Is a Major Concern | March 2013 | Program performance improved in 2012, but long-term affordability remains critical | Low |
¶ Summary
| Metric | Value |
|---|---|
| Total Reports | 39 (including testimonies) |
| Period | 2013-2025 |
| Main Reports | 30 |
| Testimonies (Congressional Hearings) | 9 |
| Reports with High CH Relevance | 19 |
¶ Recurring Themes
- Cost Explosion: From initially $233 billion to over $400 billion in procurement costs; sustainment at $1.58 trillion
- Chronic Delays: Over a decade behind the original schedule
- Block 4 Modernization: Costs rose from $10.6 billion to $16.5 billion, completion repeatedly postponed
- Readiness: Fleet mission capable rate consistently below targets (55% instead of 80%+)
- Logistics System: ALIS/ODIN functioning poorly, grounding mission-capable aircraft
- Engine Problems: F135 sustainment requires strategy review
- Spare Parts Shortage: Millions of lost or unaccounted parts
¶ Negative Headlines Summary
This section summarizes each GAO report with a headline that captures the critical findings. Update this list when new GAO reports are published.
¶ 238 Days Late: Every Single F-35 Delivered in 2024 Missed Its Deadline
(GAO-25-107632, September 2025)
All 110 aircraft delivered in 2024 averaged 238 days behind schedule. TR-3 software delays remain the primary cause. Late deliveries have become the norm, not the exception.
¶ Sustainment Crisis Continues: No End in Sight
(GAO-25-108104, 2025)
Despite years of warnings, sustainment challenges persist. DOD still lacks a viable strategy to make the F-35 affordable to operate long-term.
¶ $38 Billion Surprise: Cooling System Flaw Explodes Life-Cycle Costs
(GAO-24-107177, December 2023)
Block 4 modernization costs ballooned from $10.6 billion to $16.5 billion. A newly discovered cooling system deficiency adds another $38 billion to life-cycle costs.
¶ $2 Trillion and Counting: Total Program Costs Through 2088
(GAO-24-106909, May 2024)
While Full-Rate Production was finally achieved in March 2024, total program costs now exceed $2 trillion through 2088. Delivery delays continue unabated.
¶ 44% Cost Surge: Sustainment Estimates Jump to $1.58 Trillion
(GAO-24-106703, April 2024)
Sustainment cost estimates increased 44% in just five years—from $1.1 trillion (2018) to $1.58 trillion (2023). Meanwhile, aircraft availability has declined for five consecutive years.
¶ A Decade Late, $165 Billion Over Budget
(GAO-23-106694, March 2023)
The F-35 program is over a decade behind schedule and $165 billion over original cost estimates. Half of all 2022 deliveries were late.
¶ One Million Spare Parts Lost or Missing
(GAO-23-106098, May 2023)
Approximately one million spare parts worth $85 million are unaccounted for. Only 2% of identified losses since 2018 have been properly audited.
¶ $183 Billion Over Budget: Block 4 Pushed to 2029
(GAO-23-106047, May 2023)
The program now exceeds cost estimates by $183 billion. Block 4 modernization completion has been postponed yet again—now to 2029—with costs at $16.5 billion.
¶ Only 55% Mission Capable: Fleet Readiness Far Below Target
(GAO-23-105341, September 2023)
The F-35 fleet achieved only 55% mission capability in March 2023, far below the 80%+ target. DOD and military services must reassess their entire sustainment strategy.
¶ Grounded by Engine Problems: More F-35s Sitting Idle
(GAO-22-105995, April 2022)
Mission capable rates declined between FY2020-2021. A growing number of F-35s are grounded due to persistent engine problems.
¶ 800+ Aircraft Delivered—Still a Decade Behind
(GAO-22-105128, April 2022)
Over 800 aircraft have been delivered, yet the program remains over a decade behind schedule and $165 billion over cost estimates. Cost growth and delays continue.
¶ Engine Strategy in Disarray
(GAO-22-104678, 2022)
DOD must review and update its F-35 engine sustainment strategy. Current approach is not aligned with military service requirements.
¶ History Repeating: Modernization Plagued by Same Old Problems
(GAO-21-105282, July 2021)
The F-35 is now 8+ years late and $165 billion over expectations. Block 4 modernization is facing the exact same cost and schedule challenges that plagued initial development.
¶ $1.27 Trillion Sustainment: $6 Billion Annual Funding Gap
(GAO-21-439, April 2021)
Sustainment costs rose from $1.11 trillion to $1.27 trillion. By 2036, there will be a $6 billion annual funding gap just to keep the fleet operational.
¶ Software Development Chronically Underestimated
(GAO-21-226, March 2021)
Block 4 modernization schedule is unrealistic. DOD systematically underestimates software development effort, repeating past mistakes.
¶ ALIS Redesign Uncertain: Logistics System Still Broken
(GAO-20-665T, 2020)
Testimony reveals ongoing challenges with the ALIS redesign. Sustainment uncertainties remain unresolved.
¶ Modernization Costs Jump $1.5 Billion in One Year
(GAO-20-339, May 2020)
Modernization costs increased by $1.5 billion (14%) since May 2019. Manufacturing and modernization risks require urgent action.
¶ Mission-Capable Aircraft Grounded by Bad Data
(GAO-20-316, March 2020)
The ALIS logistics system doesn't work properly. Mission-capable aircraft are sometimes grounded simply because of inaccurate system data.
¶ $10.5 Billion Modernization Launched Without Business Case
(GAO-19-341, April 2019)
Block 4 modernization ($10.5 billion) was initiated without a complete business case. Reliability still needs significant improvement.
¶ Critical Defects Deferred Until After Production Decision
(GAO-18-321, June 2018)
DOD planned to fix critical deficiencies only after the Full-Rate Production decision—contrary to DOD's own policy. Testing revealed problems that should block production.
¶ Depot Repair: Six Years Behind Schedule
(GAO-18-75, October 2017)
Over 250 F-35s were in service, but depot repair capacity lagged six years behind schedule. Readiness and cost transparency remain problematic.
¶ Block 4 Will Cost $3.9 Billion More Than Planned
(GAO-17-690R, August 2017)
DOD expects Block 4 modernization to cost an additional $3.9 billion over five years—on top of existing budget.
¶ Test Delays Could Cost $1 Billion Extra
(GAO-17-351, April 2017)
Cascading test delays could cost over $1 billion more than budgeted. DOD needs to complete developmental testing before making new investments.
¶ ALIS Poses "Significant Risks"
(GAO-16-439, April 2016)
The Autonomic Logistics Information System (ALIS) poses significant risks requiring a comprehensive mitigation plan. Problems foreshadow years of logistics headaches.
¶ $400 Billion: The Most Expensive DOD Program Ever
(GAO-16-390, April 2016)
At $400 billion in procurement costs, the F-35 is the most expensive DOD acquisition program in history. Continued oversight urgently needed.
¶ Structural Failure, Engine Failure, Software Chaos
(GAO-15-364, April 2015)
Unexpected development changes required due to structural failure in stress testing, engine failure, and persistent software problems.
¶ $1 Trillion Sustainment Requires "Affordable Strategy"
(GAO-14-778, September 2014)
Estimated sustainment costs of $1 trillion demand an affordable strategy that DOD has yet to develop.
¶ Software Delays May Block Warfighting Capabilities
(GAO-14-322, March 2014)
Software testing delays due to late delivery, limited capabilities, and the need for extensive rework may prevent delivery of expected warfighting capabilities.
¶ Affordability Remains "Major Concern" Despite Improvements
(GAO-13-309, March 2013)
While program performance improved in 2012, long-term affordability remains a critical, unresolved concern.
¶ Sources
All reports are publicly available at gao.gov. The report numbers link directly to the respective GAO product page.
Last updated: February 4, 2026