The Boeing 787 Dreamliner has become one of the most recognizable long-haul aircraft in the world, operating everything from short transatlantic hops to record-length flights, pushing nearly 20 hours. But for all its technological achievements, one question regularly stands out among aviation fans and even frequent flyers: why does the Dreamliner offer two different engine choices? Unlike the Airbus A350 or Boeing 777X, which rely on a single engine manufacturer, the 787 can be equipped with either General Electric’s GEnx-1B or Rolls-Royce’s Trent 1000.

At first glance, it might seem like a simple case of “letting airlines choose », but the real answer is far more strategic. The engine decision touches everything from Boeing’s early program risk to long-term maintenance economics to fleet-level commonality for airlines. This article explores why the dual-engine model exists, how each option differs, and what it means for the Dreamliner program today.

Built For Choice

Boeing designed the 787 Dreamliner with two engine options to make the aircraft more appealing to a wider global market and to ensure engine manufacturers competed to deliver better efficiency, performance, and reliability. At the time of its development in the mid-2000s, airlines demanded significant fuel savings, and both GE and Rolls-Royce were pushing the boundaries of high-bypass turbofan technology, hoping to manufacture an engine that would surpass anything previously made in terms of efficiency and performance. Allowing two suppliers to produce engines reduced program risk, avoided single-supplier cost inflation, and enabled airlines to align the 787 with the engines already used across their fleets.

This strategy wasn’t new for Boeing. Earlier aircraft, like the 767 and 777, famously offered multiple engine choices, again for the same reasons. The Dreamliner simply continued that philosophy, albeit with far more advanced, next-generation engines purpose-built for the 787’s electric-bleed architecture and composite airframe.

And it worked. More than 1,100 Dreamliners have been delivered, opening over 500 new nonstop routes globally. Today, GE powers roughly two-thirds of the world’s 787s, while Rolls-Royce remains strong with operators prioritizing specific performance or maintenance models.

What Makes Each Engine Different?

Airlines do not simply pick an engine because it sounds more powerful or because they prefer one brand over another. Selecting a 787 engine is a multi-layered commercial, technical, and operational assessment that will shape decades of maintenance decisions. For many airlines, selecting the 787 in the first place is because of what the aircraft offers in terms of fuel efficiency and passenger experience.

The best way to really understand what informs the choice of engine is to dive into the specific differences and details of both engines. Fuel burn performance is one major distinguishing factor; GE advertises around 1.4% better fuel efficiency on certain flight lengths, while Rolls-Royce highlights the Trent 1000’s very high bypass ratio and performance retention over time. Time on the wing is one of the most important metrics airlines constantly turn to when weighing up which engine to choose, especially from a maintenance standpoint. GE’s GEnx has become known for long time-on-wing intervals and strong durability. Rolls-Royce had previously encountered many durability issues but has regained strength with the latest Trent 1000XE, which triples the time on wing compared to the earlier Trent 1000 TEN.

Fleet commonality also plays a part. Airlines with large GE fleets (GE90, CF6, CFM56, etc.) often choose the GEnx for training and maintenance continuity. Those that have heavily invested in Rolls-Royce, such as ANA or Virgin Atlantic, tend to lean toward the Trent 1000 for its consistency. Both manufacturers have different maintenance models. Rolls-Royce uses its signature TotalCare package, which offers predictable costs but less flexibility. GE uses a more open maintenance ecosystem, giving airlines wider MRO choices.

In practice, economics often outweighs all other considerations and is the main deciding factor for airlines when it comes to deciding on which engine to power the fleet. A 1–2% difference in fuel burn over a fleet of 30 Dreamliners flying 14-hour missions can translate into tens of millions of dollars annually. Of course, there is far more to a decision than economics alone, but ultimately, airlines are businesses that need to constantly turn over profit in order to grow and stay ahead of competitors.

Showing Off New Technologies

Both engine makers frame the 787 as a showcase of their most advanced widebody technologies. As one of the latest widebody aircraft to enter the market, and a popular model for airlines seeking to streamline long-haul fleets, it’s no surprise that both GE and Rolls-Royce see the 787 as the perfect proving ground for their initiatives. Rolls-Royce highlights the Trent 1000s three-shaft architecture, extremely high bypass ratio, advanced cooling systems, and its seamless integration with the 787’s “more-electric” design, when compared with predecessors, extracting up to 500 kW of electrical power per engine.

GE, meanwhile, emphasizes the GEnx’s composite fan blades, strong time-on-wing performance, the engine’s 99.98% dispatch reliability, and its track record powering many of the world’s longest 787 routes, including Qantas’ experimental New York–Sydney test flights. The record-breaking 19 hours, 16 minutes flight helped GE to demonstrate just what the GEnx can do: get aircraft flying further and doing so more reliably and efficiently.

Rolls-Royce’s Chief Customer Officer Ewen McDonald previously told Simple Flying that airlines conduct a comprehensive technical and economic evaluation before choosing an engine, often following a competitive bidding process between GE and Rolls-Royce. This highlights a key truth: the decision is business-driven, not brand-driven. Competition is rife between the two manufacturers, and arguably, this is a highly beneficial battle. Competition is fueling research and development, driving continual improvements from both manufacturers.

A Different Approach

The dual-engine model contrasts sharply with aircraft like the Airbus A350, where Rolls-Royce is the sole engine supplier. Airbus and Rolls-Royce argue that a single-engine solution simplifies certification and eliminates performance variability. In true Airbus fashion, simplifying everything takes the main precedence. Boeing takes the opposite view for the 787. The focus is on providing a competitive choice that benefits customers, keeps pricing fair, and ensures constant pressure on engine makers to improve reliability and efficiency.

For operators, this means assessing both the advantages and disadvantages of multiple suppliers. While choice introduces flexibility, it also creates complexity for Boeing, which must certify and support the aircraft with two independent engine architectures. When looking at Boeing’s track record, especially of late, the manufacturer has had little success when it comes to getting certifications passed.

This comparative view reinforces why the Dreamliner remains one of the few widebodies to retain dual-engine offerings. Flexibility is at the heart of the 787 and is one of the many aspects that make the aircraft unique in the airliner market.

Not Always The Best Solution

Dual-engine offerings come with complications. Rolls-Royce faced well-documented durability problems with early Trent 1000 engines, which grounded several aircraft across multiple airlines. GE engines, while more stable, have also required ongoing incremental updates and performance improvements. While both engine types have incredible strengths, issues have still cropped up, meaning that work is still needed to truly make these engines perfect.

Airlines that operate small Dreamliner fleets often avoid mixed engines because maintaining two separate support ecosystems can be costly. Maintenance staff need more training, the airline needs more parts in storage, and if there is a catastrophic engine issue, the aircraft can be grounded for extended periods. For example, Air Tanzania’s extended grounding in Malaysia highlights how supply chain delays, even temporary ones, can significantly affect smaller operators.

These risks do not negate the value of having two choices, but they do explain why airlines make their decisions carefully and rarely switch engines once a fleet is established. Risks must be evaluated before decisions are made, regardless of the benefits that an engine may have. The aviation industry operates with very high risk, so, any potential issue is not taken lightly.

Two Is Better Than One?

The Boeing 787 has two engine types because choice drives competition, lowers cost, and allows airlines to tailor performance to their network. GE’s GEnx has become the dominant option due to proven durability and availability, while Rolls-Royce’s ongoing upgrades, especially the Trent 1000XE, aim to restore competitive balance with improved time-on-wing and maintenance intervals.

For airlines, the decision is long-term and strategic. Once an engine is selected for a fleet, it shapes not only operational cost but also route capability, maintenance planning, and aircraft resale value. The Dreamliner’s dual-engine model ensures airlines have meaningful flexibility in how they operate one of the world’s most important widebody aircraft.

Looking ahead, continued upgrades from both GE and Rolls-Royce will keep the 787 competitive for decades, and ensure that engine choice remains a core part of what makes the Dreamliner unique, as well as, of course, the rather interesting passenger windows.