What caused the Boeing 737 MAX door plug incident and how does it relate to Spirit AeroSystems?

On January 5, 2024, an Alaska Airlines Boeing 737 MAX 9 lost a door plug mid-flight — a panel that covers an unused emergency exit position — departing Portland, Oregon. The door plug was blown out due to missing bolts that should have secured it. Investigation found that Spirit AeroSystems manufactured the fuselage section in Wichita, Kansas; the section was delivered to Boeing's Renton, WA assembly facility; Boeing records showed the bolts were missing from the installed door plug at delivery. Both Spirit and Boeing bore responsibility — Spirit for delivering a fuselage with a potentially non-conforming door plug area, and Boeing for failing to catch the issue in final assembly. The incident resulted in FAA-mandated production rate caps on 737 MAX, additional quality inspections, and Congressional scrutiny. It accelerated Boeing's discussions about re-acquiring Spirit AeroSystems to gain direct quality control over fuselage manufacturing.

How does CFM International work as a joint venture between GE and Safran?

CFM International is a 50/50 joint venture between GE Aerospace (U.S.) and Safran Aircraft Engines (France), established in 1974. CFM designs, certifies, manufactures, and supports commercial narrowbody aircraft engines — primarily the CFM56 (legacy, installed on Boeing 737 Classic/NG and original Airbus A320 family) and the LEAP (current generation, installed on Boeing 737 MAX and Airbus A320neo/A321neo). The partnership structure works as follows: GE and Safran each develop specific engine modules (GE develops the high-pressure compressor and combustor; Safran develops the fan and low-pressure turbine); modules are shipped to CFM facilities for final assembly; CFM sells the complete engine to Boeing and Airbus. CFM has delivered over 35,000 engines, making it the world's most successful commercial engine partnership. GE and Safran share R&D costs, manufacturing investments, and profits equally through the JV structure.

Why do jet engine companies earn more from aftermarket services than from selling new engines?

Jet engines are often sold at thin margins or even at a loss — the real profitability comes from the 20-30 year aftermarket relationship. This 'razor and blades' model works because: engines require mandatory maintenance — FAA airworthiness regulations require regular engine overhauls (shop visits every 5,000-7,000 flight cycles); the engine OEM has exclusive or preferred access to proprietary parts — GE's engine parts are engineered to GE specifications and often cannot be substituted; certified repair capabilities are concentration — only facilities certified by GE can perform overhauls to airworthiness standards; and data and technical manuals are controlled — only the OEM holds complete engine configuration data and repair procedures. A typical LEAP engine sold for ~$10 million generates $3-5 million in annual aftermarket spending over 25+ years of operation — the Net Present Value of aftermarket services per engine substantially exceeds the engine selling price. This creates GE's durable, recurring, high-margin aftermarket business.

brimindinvest.com / compare / ge-vs-spr-aerospaceLIVE

GE

GE Aerospace · Industrials - Aerospace & Defense

$357.64

+25.36% this month

VERSUS

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SPR

Spirit AeroSystems Holdings, Inc. · Industrials - Aerospace Manufacturing

N/A

N/A this month

Scoreboard verdict

Across AI score, momentum, valuation, upside, operating margin

GE

0

SPR

0

MIXED SETUP

Comparison scoreboard

MIXED SETUP

AI Score

GE 40.7

SPR N/A

1Y Return

GE +51.70%

SPR N/A

Fwd P/E

GE 38.60

SPR N/A

Target Up.

GE +4.67%

SPR N/A

Op. Margin

GE 20.21%

SPR N/A

Metrics last refreshed: 6/20/2026

Quick take

GE vs SPR Stock Comparison: AI Score, Valuation, Performance and Upside

GE (GE Aerospace) and SPR (Spirit AeroSystems) are both aerospace companies but at dramatically different financial health and strategic positions — GE Aerospace is a premium jet engine business with a growing high-margin aftermarket services franchise and strong financial profile as a newly independent company, while Spirit AeroSystems is a financially stressed aerostructures manufacturer whose revenue is heavily dependent on Boeing 737 MAX delivery rates and faces quality control and balance sheet challenges.

GE vs SPR is premium jet engine OEM with durable aftermarket services cash flows (GE Aerospace's LEAP engine dominance and 40,000+ installed base generating decades of high-margin overhaul and parts revenue with military engine diversification) versus aerostructures contract manufacturer with Boeing production risk (Spirit AeroSystems' sole-source 737 MAX fuselage position creating revenue dependency on Boeing's production rate with balance sheet stress and quality execution challenges) — durable aftermarket engine business versus cyclical aerostructures dependent on Boeing.

Live analysis · updated 6/20/2026

GE and SPR are closely matched — they split the tracked metrics evenly.

Normalized 1Y performance

GE

SPR

Not enough data to chart yet.

Recent returns

GE

SPR

Analyst price targets & sentiment

GE · 18 analysts

STRONG BUYHOLDSTRONG SELL

Strong Buy (1.5/5.0)

Price target range

analyst low$196.11
analyst mean$350.95
current price$357.64

+4.7% upside to analyst mean

SPR

Price target data unavailable

N/A

Who should consider this stock?

GE may suit investors who:

→Want a pure-play commercial aviation engine business with the dominant narrowbody engine (LEAP) installed on Boeing 737 MAX and Airbus A320neo — the world's most-produced jet families — generating decades of high-margin aftermarket services revenue
→Value GE Aerospace's aftermarket services business as a durable recurring revenue stream that grows as the installed engine base ages and requires overhaul
→Believe commercial aviation's long-term growth trend (global passenger traffic growing 4-5% annually over 20 years) creates structural demand for jet engines and services that withstands near-term cycle volatility

SPR may suit investors who:

→Believe Boeing's 737 MAX production will recover to normal rates and that Spirit's revenue will benefit from the production ramp
→See potential Boeing re-acquisition of Spirit as an event-driven opportunity — Boeing has discussed bringing Spirit back in-house to improve quality control, which could involve an acquisition premium for SPR shareholders
→Understand aerostructures as a cyclical, low-margin aerospace manufacturing business and accept Spirit's higher risk profile relative to GE Aerospace's premium engine franchise

Performance & AI score

Metric	GE	SPR
AI score	40.7	N/A
AI rank	#1020	N/A
Latest close	$357.64	N/A
1M return	+25.36%	N/A
6M return	+22.40%	N/A
1Y return	+51.70%	N/A

$10,000 invested — hypothetical growth (dividends reinvested)

How much would $10,000 be worth today if invested at the start of each period, with all dividends reinvested?

Period	GE	SPR
1Y ago	$15.16K (+51.6%) started 2025-06-18	N/A
5Y ago	$56.43K (+464.3%) started 2021-06-21	N/A
10Y ago	$29.98K (+199.8%) started 2016-06-20	N/A

Hypothetical — past performance does not guarantee future results.

Valuation & upside potential

Metric	GE	SPR
Market cap	$350.33B	N/A
Trailing P/E	41.65	N/A
Forward P/E	38.60	N/A
Price/Sales	6.87	0.73
EV/Revenue	7.47	N/A
Analyst target	$350.95	N/A
Target upside	+4.67%	N/A

Growth, profitability & risk

Metric	GE	SPR
Revenue growth	24.70%	N/A
Earnings growth	-1.80%	N/A
EPS growth	-1.80%	N/A
FCF margin	+11.73%	N/A
Operating margin	20.21%	N/A
Profit margin	17.86%	N/A
ROIC proxy	45.43%	N/A
Return on equity	45.43%	N/A
Dividend yield	0.56%	N/A
Beta	1.38	-0.24
Debt/equity	116.53	N/A
Current ratio	1.01	N/A
Quick ratio	0.65	N/A

Drawdown & downside risk

Lower drawdown and smaller single-period drops generally indicate a smoother ride, though they do not guarantee lower future risk.

1Y risk snapshot

GE max drawdown20.97%

SPR max drawdownN/A

GE max wkly drop11.99%

SPR max wkly dropN/A

5Y risk snapshot

GE max drawdown44.94%

SPR max drawdownN/A

GE max wkly drop16.89%

SPR max wkly dropN/A

10Y risk snapshot

GE max drawdown81.19%

SPR max drawdownN/A

GE max wkly drop28.20%

SPR max wkly dropN/A

Performance metrics by period

Period	Metric	GE	SPR
1Y	Growth	+51.61%	N/A
	CAGR	+51.70%	N/A
	Sharpe ratio	1.34	N/A
	Max drawdown	20.97%	N/A
	Max daily drop	7.38%	N/A
	Max wkly drop	11.99%	N/A
5Y	Growth	+453.98%	N/A
	CAGR	+40.91%	N/A
	Sharpe ratio	1.12	N/A
	Max drawdown	44.94%	N/A
	Max daily drop	11.10%	N/A
	Max wkly drop	16.89%	N/A
10Y	Growth	+168.68%	N/A
	CAGR	+10.39%	N/A
	Sharpe ratio	0.33	N/A
	Max drawdown	81.19%	N/A
	Max daily drop	15.16%	N/A
	Max wkly drop	28.20%	N/A

Business comparison

Category	GE	SPR
Company	GE Aerospace	Spirit AeroSystems Holdings, Inc.
Sector	Industrials	Industrials - Aerospace Manufacturing
Industry	Aerospace & Defense	N/A
Core business	GE Aerospace is a standalone aerospace engine company following GE's breakup into three separate companies (GE Aerospace, GE Vernova power, and GE HealthCare). GE Aerospace designs, manufactures, and services commercial and military jet engines — including the LEAP engine (joint venture with Safran as CFM International, powering Boeing 737 MAX and Airbus A320neo), GE90/GE9X for Boeing 777/787, CF6, and military engines for the F110, F404/F414 programs. The aftermarket services business (MRO — maintenance, repair, and overhaul) generates substantial recurring revenue from the installed base of engines in service.	Spirit AeroSystems is a major aerostructures manufacturer — producing fuselages, pylons, nacelles, and other major airframe structures for Boeing and Airbus. Spirit's primary product is the Boeing 737 MAX fuselage (approximately 55% of revenue historically), along with Boeing 787 and 767 sections and Airbus A320 family pylons. Spirit was spun off from Boeing in 2005 and has struggled with quality issues, balance sheet stress from Boeing production slowdowns, and the consequences of the 737 MAX groundings.
Investor focus	Investors track GE Aerospace's engine delivery volumes (LEAP deliveries constrained by supply chain), aftermarket services revenue growth (high-margin engine overhaul and parts for the installed base), military engine program wins and NGAD/F-15 engine competitions, free cash flow conversion, and the transition to a pure-play aerospace company after the GE conglomerate breakup.	Investors track Spirit's Boeing delivery rates (directly affecting Spirit's 737 production volume and revenue), balance sheet and liquidity (Spirit has carried significant debt and faced covenant concerns during Boeing production slowdowns), quality control performance (the January 2024 Alaska Airlines door plug incident involved a 737 MAX fuselage manufactured by Spirit), and Boeing's potential re-acquisition of Spirit.

GE strengths

→CFM International LEAP engine dominates narrowbody commercial aviation — the LEAP engine is installed on Boeing 737 MAX and Airbus A320neo (the world's two best-selling jet families); each LEAP engine sold creates decades of high-margin aftermarket services revenue (engine overhauls, parts, technical support) from the growing installed base
→Aftermarket services provide durable, high-margin recurring revenue — jet engines require regular overhauls every 5-7 years and ongoing parts/services; GE's installed base of 40,000+ commercial engines in operation generates predictable, premium-priced services revenue that grows as the fleet ages
→Military engine portfolio provides defense diversification — GE Aerospace's military engines power F-16, F-15, F/A-18, and other platforms; U.S. and allied defense spending provides stable military engine revenue alongside the commercial cycle

SPR strengths

→Sole-source supplier of Boeing 737 MAX fuselage — Spirit is the only supplier of the 737 MAX fuselage section; Boeing cannot easily dual-source this critical component, giving Spirit pricing stability and a locked-in supply relationship for the life of the 737 MAX program
→Airbus A320 pylon work diversifies Boeing concentration — Spirit's Airbus nacelle and pylon work provides revenue diversification beyond Boeing; growing to reduce Boeing revenue concentration is a strategic priority
→Potential Boeing re-acquisition provides acquisition premium upside — Boeing has discussed re-acquiring Spirit to improve quality control oversight; an acquisition at a premium would benefit Spirit shareholders

Risks to watch — GE

→LEAP supply chain execution — CFM International's LEAP delivery rates have been constrained by supply chain bottlenecks (castings, forgings, materials); failure to ramp deliveries limits Boeing and Airbus ability to deliver aircraft and constrains GE Aerospace revenue growth
→Commercial aviation cycle exposure — aircraft orders and deliveries are highly cyclical; airline financial health affects aircraft order rates, and engine deliveries slow during aviation downturns (COVID caused massive demand disruption)
→Competition from Pratt & Whitney GTF — Pratt & Whitney's Geared Turbofan (GTF) is the other narrowbody engine choice (on Airbus A320neo, competing with LEAP-1A); GTF gearbox durability issues have created near-term competitive advantage for LEAP but P&W will resolve them

Risks to watch — SPR

→Boeing production slowdowns directly impair Spirit revenue — Spirit's revenue is largely a function of Boeing delivery rates; Boeing 737 MAX production restrictions (FAA oversight, Boeing's own quality holds) directly reduce Spirit's revenue and cash flow
→Quality control failures creating financial and reputational risk — the January 2024 Alaska Airlines 737 MAX door plug blowout involved Spirit-manufactured fuselage sections; quality failures lead to production holds, customer penalties, and potential liability exposure
→Balance sheet fragility — Spirit has carried high debt levels and has required liquidity assistance from Boeing during production disruptions; thin margins on aerostructures manufacturing leave little buffer for production slowdowns or quality remediation costs

Frequently asked questions

In aerospace, Original Equipment Manufacturers (OEMs) are companies like Boeing, Airbus, Lockheed Martin, and Northrop Grumman that design, integrate, and certify the final aircraft (the 'type certificate' holder responsible for airworthiness). Tier 1 suppliers provide major subsystems and large structural components directly to OEMs. GE Aerospace and its CFM International joint venture (with Safran) are effectively Tier 1 engine suppliers — GE designs and manufactures the complete propulsion system to Boeing/Airbus specification and holds its own FAA type certificate for the engine. Spirit AeroSystems is a Tier 1 aerostructures supplier — it manufactures large fuselage sections, pylons, and nacelles to Boeing's design and delivers them directly to Boeing's final assembly line. The distinction matters financially: engine OEMs like GE have stronger pricing power, IP ownership, and aftermarket services capture than aerostructures manufacturers who are competing on manufacturing efficiency.

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