Scale Economies and New Trade Theory

The Boeing-Airbus Duopoly

Commercial aircraft is one of the most complex manufactured products on earth. A single Boeing 787 contains approximately 2.3 million parts, requires 800 suppliers across 17 countries, and takes months to assemble.

There are exactly two companies in the world capable of producing competitive wide-body commercial jets: Boeing (US) and Airbus (Europe). This is not because only two countries have the technical capability to develop aviation industries. Canada, Brazil, and China all have aircraft companies — but they compete primarily in the regional jet segment. The wide-body market is a duopoly.

Why? Not because of comparative advantage in the Ricardo or H-O sense. Both the US and Europe have capital, skilled labor, and engineering talent. The reason is economies of scale — and understanding this requires going beyond classical trade theory entirely.

I. The Limits of Classical Theory

Both comparative advantage and Heckscher-Ohlin theory assume constant returns to scale: doubling inputs doubles output. Under this assumption, there’s no particular reason for production to concentrate geographically; you’d expect each country to produce some of everything in proportion to its endowments.

But the real world shows something different: trade happens even between identical countries (France and Germany export similar manufactured goods to each other), and production concentrates in specific locations (Silicon Valley for software, Stuttgart for luxury cars, the Rotterdam-Antwerp corridor for chemicals) without obvious endowment-based reasons.

This is where New Trade Theory, developed primarily by Paul Krugman in the late 1970s (earning him the 2008 Nobel Prize), fundamentally changed the field.

II. New Trade Theory: The Role of Scale

The key insight is that increasing returns to scale — where each additional unit costs less to produce than the previous one — have powerful implications for trade patterns.

Why Scale Economies Cause Trade Concentration

When an industry has strong scale economies:

Larger producers have lower average costs — they can undercut smaller competitors
First-mover advantage matters — whoever achieves scale first gains a lasting cost advantage
Markets tip toward concentration — rather than many producers in many countries, a few large producers in a few locations dominate globally

In the aircraft example: Boeing and Airbus each invested tens of billions in developing the 787 and A350 respectively. These R&D costs are largely fixed. The more planes each sells, the lower the per-unit cost. A hypothetical third entrant would start at a massive cost disadvantage — having to spread its fixed costs over far fewer planes.

This explains the duopoly without any appeal to comparative advantage.

The Home Market Effect

Krugman’s formal model shows that industries with scale economies tend to concentrate in large home markets. The US aerospace industry emerged from a large domestic market (military procurement + civilian aviation) that allowed Boeing to achieve scale before competing internationally. That scale then became a persistent competitive advantage.

This is the “home market effect”: countries with large domestic demand for a good tend to become exporters of that good, because scale economies allow domestic producers to achieve lower costs.

III. Intra-Industry Trade: The Puzzle Krugman Solved

Classical theory predicts inter-industry trade: countries export what they’re relatively good at and import what they’re relatively bad at. You’d expect England to export financial services to Italy and import Italian wine.

But in practice, a large share of world trade is intra-industry trade: countries simultaneously import and export the same category of goods. Germany exports BMWs to France and imports Peugeots. The US exports apples to Canada and imports Canadian apples.

This makes no sense under classical theory. Why would consumers buy both domestic and foreign versions of the same good?

Krugman’s answer: product differentiation + love of variety. Consumers value variety. Even if German and French cars are functionally similar, some consumers prefer German engineering, others prefer French styling. Intra-industry trade allows consumers in each country access to a wider range of varieties than could be sustainably produced domestically.

This “new new trade theory” explains:

Why rich countries trade mostly with each other (similar incomes → similar tastes → demand for variety)
Why trade between similar countries is so large
Why trade liberalization generates gains even when countries have similar endowments

IV. The iPhone Value Chain: Applied New Trade Theory

The iPhone is assembled in China, but most of its value is created elsewhere. A breakdown of the iPhone’s value chain:

Component/Activity	Location	Value Captured
Design, OS, software, brand	United States (Apple)	~40% of value
Display (OLED)	South Korea (Samsung)	~15%
Chip (A-series)	Taiwan (TSMC manufacturing)	~10%
Camera sensors	Japan (Sony)	~5%
Assembly	China (Foxconn)	~3-5%
Other components	Multiple countries	~25%

China captures only a small fraction of the iPhone’s total value despite doing the physical assembly. This is the “smile curve” of global value chains: the high-value activities are at the two ends (R&D and brand at one end, customer experience at the other) while assembly — the middle of the curve — captures the least value.

The distribution of iPhone value reflects who has achieved scale and specialization in each activity:

TSMC dominates advanced chip manufacturing through decades of scale investment
Samsung dominates OLED through similar scale advantages
Apple dominates design and software through network effects and brand investment

V. Strategic Trade Policy

New Trade Theory has a troubling implication: governments can theoretically improve national welfare by supporting domestic firms in scale-economy industries.

If an industry is a natural oligopoly (only 2-3 firms globally), and if being in that oligopoly generates large profits that would otherwise go to foreign firms, then subsidizing your domestic firm to achieve scale could pay off.

The Boeing-Airbus subsidy war is the most prominent real-world example. Airbus was created in 1970 as a European consortium with significant government support, explicitly to break Boeing’s dominance. The US retaliated by pointing to defense procurement as implicit Boeing subsidies. Both sides are right — both firms have received substantial government support.

The WTO ruled against both parties in parallel cases (2004–2019), ultimately concluding that both had received illegal subsidies. The total disputed amounts ran to tens of billions of dollars.

The strategic trade policy problem: If it works, everyone will try it. If all countries subsidize their aerospace industries, the result is global overcapacity, not national competitive advantage. The game theory is messy, and empirical evidence on whether strategic trade policy actually pays off is mixed.

Why It Matters

Scale economy logic explains the structure of today’s global economy:

Why semiconductor manufacturing is concentrated in Taiwan and South Korea
Why the US dominates software platforms (winner-take-all scale economies)
Why it’s so hard for newcomers to break into industries with high fixed costs
Why industrial policy might be justifiable in specific high-scale sectors

It also explains why trade policy debates today often focus not on tariffs but on subsidies, procurement, and industrial policy — because in scale-economy industries, the game is about who achieves scale first, not who has the lowest wages.