Airline “hubs” are airports where a carrier concentrates flights in order to connect passengers across its broader network. A hub functions as a centralized point where travelers can arrive on one flight and connect to many others, often within coordinated “banks” of departures. This system allows airlines to maximize efficiency and connectivity, but it also creates competitive concerns. The larger the hub, the more attractive it becomes to travelers and corporate clients. When growth is constrained by airport capacity, however, certain advantages can translate into market power for dominant airlines, and market power can trigger antitrust scrutiny.
Recently, Newark Liberty International Airport has been in the news for persistent air traffic control staffing shortages and equipment malfunctions. It even got parodied by Saturday Night Live in a now viral skit. Jokes aside, Newark’s longstanding challenges ultimately led regulators to impose limits on the number of flights the airport can accommodate. As a result, its largest tenant, United Airlines, cut dozens of daily departures while the airline called for more “slot control” at Newark. These issues shine a spotlight on some of the antitrust questions that arise when hubs attempt to balance safety restrictions with competitive concerns.
Hubs and Antitrust Risk
Because hub operations benefit from scale, the carrier with the largest presence can often set schedules and prices in ways that smaller rivals cannot easily match. The concern for regulators is that, at airports where takeoff and landing opportunities are limited, a dominant hub airline might exclude competition simply by holding onto its share of flights. U.S. antitrust authorities have responded at times with remedies such as requiring airlines to give up “slots” (the specific authorizations to take off or land at set times), mandating gate access, or even blocking merger deals altogether. For example, in a 2013 settlement to resolve an antitrust merger challenge, the Department of Justice (DOJ) required US Airways and American Airlines to divest slots, gates, and related facilities at seven key airports—including Reagan National, LaGuardia, Boston, Chicago, Dallas, Los Angeles, and Miami—as a way to increase competitive access for low-cost carriers and promote system-wide competition.
Newark’s Role in the Debate
Newark Airport has long illustrated the problems with hub dynamics. Specifically, United Airlines maintains a strong presence at the airport, with public data showing it controls well over half of the airline traffic into and out of Newark. In 2015, the Department of Justice sought to block United from acquiring additional slots at Newark from Delta, warning that the purchase would entrench an already dominant position. The Assistant Attorney General at the time, Bill Baer, delivered remarks regarding the DOJ’s injunction stating: “We know from experience what happens when competition is allowed to flourish. This transaction will have the opposite effect.” United later abandoned the deal.
United’s dominant position at Newark is compounded by the airport’s capacity constraints. Specifically, in 2016, the Federal Aviation Administration (FAA) altered Newark’s scheduling classification. Previously, it was designated a “Level 3” airport, meaning every takeoff and landing required a formally allocated slot that was tightly controlled and monitored. The reclassification to “Level 2” did not remove its capacity limits but replaced strict slot allocation with “schedule facilitation,” where airlines coordinate their requested schedules with an airport facilitator. The aim was to allow more flexibility, but in practice, the airport remained highly congested, and prime flight times remained scarce.
Most recently, in September 2025, the FAA extended Newark’s hourly flight caps through October 2026. The order limits operations to 72 total flight movements per hour—36 arrivals and 36 departures—slightly above the previous limit of 68. The FAA cited persistent congestion and shortages of air traffic controllers as reasons for continuing the cap. But it also has competitive effects. By fixing a ceiling on the total number of flights, the FAA effectively prevents rival airlines from expanding service in meaningful ways. For United, the dominant carrier, the cap helps stabilize operations but also arguably preserves its position by limiting the scope for challengers to grow. The overarching question, of course, is how this will all impact consumer pricing. For now, United has vowed to keep prices low for flights out of Newark, but as demand rebounds and capacity remains restricted (in terms of supply and the competitive landscape), there is no telling how long that deal will last.
Will Antitrust Enforcement in Aviation Shift?
In the past, Courts and regulators have blocked or unwound arrangements they deemed harmful to competition. For example, the American–JetBlue “Northeast Alliance” was enjoined in 2023, and JetBlue’s proposed acquisition of Spirit Airlines was halted in 2024. These cases reflected a growing willingness to intervene where regulators believed consolidation or coordination would reduce consumer choice, especially at capacity-constrained airports. Whether the current Trump administration carries this mantle of enforcement in the aviation space remains to be seen.
The Newark story shows a potential shift in enforcement priorities. Indeed, it seems like the regulatory limitation exacerbate, rather than ease competitive concerns. On the one hand, DOJ actions in the past sought to keep United’s market share from increasing further and to preserve opportunities for low-cost carriers. On the other, the FAA’s recent caps—introduced for operational reasons—could have the side effect of freezing the competitive landscape. That combination illustrates the complexity of managing both reliability and competition in modern aviation and highlights the tension between keeping flights on time and ensuring that dominant hub carriers do not entrench themselves further behind the shield of limited capacity.
