The urban air mobility revolution is approaching faster than many realize. Electric vertical takeoff and landing (eVTOL) aircraft -- essentially next-generation helicopters powered by batteries instead of jet fuel -- represent a transformative leap in urban transportation. JPMorgan analysts estimate this emerging market could reach $1 trillion by 2040, as electric aircraft transform transportation between and within cities.

While many start-ups are pursuing this opportunity, one company has rapidly distinguished itself through exceptional execution and strategic partnerships. With strong order flow, key industrial partnerships, and a clear path to production, Archer Aviation (ACHR -1.32%) warrants serious attention from growth investors.

An eVTOL aircraft flying through a city.

Image Source: Getty Images.

Yet beneath this promising exterior lies a potential risk that could significantly impact long-term shareholders. Here's why I'm both excited and concerned about Archer's trajectory.

Breaking ground in Georgia

I'm particularly impressed by Archer's new 400,000-square-foot manufacturing facility in Covington, Georgia. This milestone represents a crucial step in the company's journey from concept to commercialization. Initial production is scheduled for early 2025, with plans to reach two aircraft per month by the end of the year.

The facility's ultimate target of 650 aircraft annually by 2030 demonstrates what I consider a well-balanced approach to scaling production. The manufacturing ramp-up strategy shows both ambition and pragmatism, key traits I look for in early-stage aerospace companies.

Validation through partnerships

What catches my attention next is Archer's recent exclusive agreement with Anduril Industries to develop military aircraft. This partnership becomes even more intriguing when considering Anduril's recent moves in artificial intelligence and autonomous systems. Speaking to this point, the defense technology company just announced a strategic partnership with OpenAI to advance autonomous defense capabilities, particularly in counter-drone applications.

I see powerful synergies between Archer's eVTOL expertise and Anduril's Lattice software platform, which enables a single operator to control multiple autonomous systems across different domains. The development of autonomous or optionally piloted military aircraft could open up entirely new mission capabilities for the Department of Defense.

Furthermore, the $430 million capital raise supporting this partnership, which included participation from strategic investors like United Airlines and Wellington Management, reflects the market's recognition of these possibilities.

Meanwhile, on the commercial front, a joint venture with Japan Airlines and Sumitomo Corp. could generate up to $500 million in aircraft orders. These partnerships have helped push Archer's indicative order book beyond $6 billion, validating both its technology and business model.

Defense sector potential

I'm intrigued by the market's seeming underappreciation of Archer's defense opportunities. Major defense contractors like Lockheed Martin, General Dynamics, and Northrop Grumman have historically outperformed the S&P 500 by substantial margins over extended periods. This outperformance stems from lucrative, multiyear government contracts and consistently strong bipartisan support for defense spending.

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With a market capitalization of just $3.6 billion at recent prices, Archer's current valuation appears to largely ignore its defense potential through the newly minted Anduril partnership. Developing specialized hybrid VTOL aircraft for military applications could open up decades of steady, high-margin revenue streams.

Many successful defense contractors began as small, specialized technology companies before growing into industry giants. I believe Archer's early moves into this sector could prove similarly transformative for the company and its shareholders-but only if it remains independent long enough to capitalize on this opportunity.

Disciplined financial management

I'm particularly impressed with Archer's financial discipline for a pre-revenue company. With over $500 million in cash and stable quarterly spending, the company's balance sheet screens as exceptionally strong.

Moreover, Archer's 12.4% share count increase over the prior three years stands well below its peers' 21% average dilution rate. This conservative approach to capital management suggests to me that Archer's leadership team deeply values shareholder interests.

That's a key trait I look for when investing in cutting-edge growth companies.

A partnership's hidden risk

Here's where my concerns begin to surface. Global auto giant Stellantis (STLA 0.38%), formed by the 2021 merger of Fiat Chrysler and PSA Group, owns a whopping 20.2% stake in Archer. While the automaker's manufacturing expertise and financial support are crucial to Archer's development, I believe this substantial position could foreshadow a full acquisition attempt.

Stellantis brings invaluable automotive mass production knowledge to the table and has committed significant resources to Archer's success. However, the automaker is facing its own challenges.

The recent unexpected departure of CEO Carlos Tavares and the company's declining European market share have created uncertainty around its strategic direction. This turbulence at Archer's largest shareholder and key manufacturing partner adds another layer of complexity for investors to consider.

To sum up, I worry that Stellantis, seeking to transform its business amid industrywide electrification challenges, might view acquiring Archer as a strategic necessity. Even at a significant premium, such a scenario might deny shareholders the full value of Archer's long-term potential across air taxi services, aircraft sales, and defense contracting.

The investing takeaway

In my view, Archer Aviation exemplifies the rare start-up that has successfully navigated the challenging path from concept to imminent production. However, the partnership that helped enable this success might ultimately limit shareholders' returns.

Investors must weigh the company's tremendous potential against the possibility that Stellantis' significant ownership stake could lead to a premature acquisition, cutting short what could be a much longer and more valuable growth story. After all, Stellantis has a well-established history of acquiring innovative companies with a potential technological moat -- and Archer fits that description to a tee.