Fiberglass For Aircraft, Advantages and Disadvantages

Fiberglass is used in the manufacture of a wide range of industrial and consumer goods, and aircraft production is one of the most demanding among them. Fiberglass for aircraft is specified primarily because of its low weight, which directly affects fuel consumption and payload capacity. It also resists corrosion far better than the aluminium alloys it often replaces in secondary structures.

Fiberglass is made from glass fiber, which comes in several types depending on the intended application. The material contains silica, calcium, and other compounds that give it considerable strength for its weight. It is worth being accurate about how it compares with other composites, however. Carbon fiber has substantially higher tensile strength and stiffness than fiberglass. What fiberglass offers instead is a strong balance of adequate strength, excellent corrosion resistance, and significantly lower cost, which is why both materials are used side by side in modern aircraft rather than one replacing the other.

Commonly Used in the Aircraft Industry

Components built on a fiberglass base are classified as composite materials. The defining characteristic of a composite is that its constituent materials retain their individual identities rather than dissolving into one another, with the fibers providing strength and the surrounding matrix holding them in place and transferring load between them. The main composite categories used in aviation are carbon fiber, fiberglass, and aramid fibers, each combined with a resin matrix system.

Fiberglass is one of the most widely used composite materials in aircraft manufacturing, particularly for secondary structures and interior components. It was also among the first composites adopted in cars and boats, with widespread commercial use beginning around the 1950s. To understand which specific glass fiber grades are used in these applications, our overview of the different types of fiberglass based on material characteristics explains how E-glass and S-glass differ in performance.

The History of Fiberglass Use in Aviation

Fiberglass has been used in transport manufacturing for decades, across cars, boats, and aircraft. Composite materials in aviation date back to the World War II era, when early glass fiber reinforced plastics were first applied to aircraft components. As manufacturing techniques matured through the following decades, composites attracted steadily more attention and their use expanded considerably.

Beyond powered aircraft, fiberglass is also common in gliders and light sport aircraft, where its combination of low weight and moldability into aerodynamic shapes is particularly valuable.

It is important to be precise about the widely quoted composite percentages in modern aircraft, because these figures are frequently misreported. The Boeing 787 Dreamliner, which entered commercial service in 2011, is approximately 50 percent composite by weight. However, that figure refers to composite materials overall, and the primary structural composite in the 787 is carbon fiber reinforced polymer rather than fiberglass. Fiberglass in modern airliners is concentrated in specific roles where its particular properties matter most, especially radomes, fairings, interior panels, and insulation.

The radome application deserves particular mention because it illustrates why fiberglass is not simply a cheaper substitute for carbon fiber. Radomes house radar and communication antennas, and the covering must be transparent to radio waves. Carbon fiber is electrically conductive and would block those signals, whereas fiberglass is not, which makes it the correct engineering choice regardless of cost. Our companion article on lightweight fiberglass in the aircraft industry covers these application areas and the fuel efficiency benefits in more depth.

While the use of composites continues to expand, the material is not without limitations. Understanding both sides is essential for anyone specifying or maintaining these structures, and the sections below examine each in turn.

Advantages of Fiberglass for Aircraft

The foremost advantage of fiberglass for aircraft is low weight. Reducing structural mass lowers fuel burn across the entire operating life of the airframe, which is why weight reduction dominates so many design decisions in aviation. This single factor explains much of the industry’s move toward composite construction.

Fiberglass composites also deliver an excellent strength-to-weight ratio. On an equal-weight basis, a well-designed glass fiber laminate compares favourably with aluminium, although it is important to note that this advantage lies in the ratio rather than in absolute strength. Composite laminates are strongest along the fiber direction, which means their performance depends heavily on how the layup is engineered for the loads a component will actually carry.

The material also produces a smooth moulded surface finish directly from the tool, reducing the additional surface preparation that metal components often require. Its resistance to corrosion is a further significant benefit, since corrosion is a persistent maintenance burden for aluminium airframes, particularly in coastal and humid operating environments. Fiberglass laminates also tolerate flexing and resist crack propagation well, and a properly designed composite component can offer a long fatigue life.

One correction is worth making to a common misconception, however. Composite structures do still require inspection and maintenance. What differs is the nature of that maintenance rather than its absence, and the following section explains why.

Property	Fiberglass	Carbon Fiber	Aluminium
Tensile strength	Good	Highest	Moderate
Stiffness	Moderate	Very high	Moderate
Weight	Light	Lightest	Heavier
Corrosion resistance	Excellent	Excellent	Requires protection
Radio transparency	Yes	No, conductive	No, conductive
Damage visibility	Can be hidden internally	Can be hidden internally	Usually visible as deformation
Relative cost	Lower	Highest	Moderate
Typical aircraft use	Radomes, fairings, interiors	Primary structure, wings	Traditional airframe structure

Disadvantages and Limitations of Fiberglass for Aircraft

Composite materials including fiberglass resist breakage and corrosion well, but this same durability creates a genuine inspection challenge. Internal damage within a laminate is often not visible from the surface, which means a component can appear sound while containing delamination or fiber breakage beneath an intact outer layer.

This contrasts with aluminium, which typically deforms visibly when it sustains impact, giving maintenance personnel an immediate indication that something is wrong. For composites, the Federal Aviation Administration notes that specialised non-destructive inspection methods such as tap testing and ultrasonic inspection are used precisely because visual examination alone cannot reliably detect subsurface damage in laminated structures.

Repair also presents difficulties. When a composite component is damaged, restoring it correctly requires trained technicians, controlled conditions, and specific procedures for the material system involved. This makes composite repair more demanding and often more costly per instance than equivalent metal repair, even though composites may require intervention less frequently overall.

Thermal Limitations

The resin matrix that binds the glass fibers is the limiting factor in a composite’s temperature performance, not the glass itself. Many aerospace resin systems begin to soften and lose mechanical properties in the region of 150°C, with the exact threshold depending on the resin chemistry and cure process used. This is well below the point at which the glass fiber itself is affected.

At higher temperatures, in the region of 300°C and above, the structural integrity of a standard composite laminate can be compromised significantly. In a fire scenario, the organic resin component burns and can generate smoke containing products of combustion, which is a recognised consideration in aircraft interior material selection. This is precisely why aviation interior materials are subject to strict flammability, smoke, and toxicity requirements, and why phenolic resin systems, which offer better fire performance and lower smoke emission, are widely specified for cabin components.

It is worth distinguishing clearly between the two components here. Glass fiber itself is noncombustible and does not burn. The resin matrix is the combustible element, which is why the resin system chosen has a decisive influence on the fire behaviour of the finished part. Our article on fiberglass cloth and resin explains how the two components work together and how resin selection affects performance.

Limitation	Practical Implication	How It Is Managed
Hidden internal damage	Surface may look intact while laminate is compromised	Ultrasonic and tap testing inspection regimes
Complex repair	Requires trained technicians and controlled conditions	Approved repair procedures and certified facilities
Resin softening near 150°C	Loss of mechanical properties at elevated temperature	Resin selection matched to service temperature
Smoke from burning resin	Cabin safety consideration in fire scenarios	Phenolic resins and regulatory flammability testing
Directional strength	Strength varies with fiber orientation	Engineered layup schedules for expected loads
Lightning strike conductivity	Composites do not conduct like metal skins	Integrated conductive mesh or foil layers

Cost in Context

A common misconception is that fiberglass is an expensive material. Within the composites family it is in fact the more economical option, considerably cheaper than carbon fiber while still delivering strong performance for many applications. This cost advantage is one of the main reasons fiberglass remains widely used even as carbon fiber dominates primary structural applications.

The more meaningful cost comparison in aviation is total lifecycle cost rather than material purchase price. Reduced structural weight lowers fuel consumption across thousands of flight hours, and corrosion resistance reduces the maintenance burden that affects aluminium structures over time. Set against these savings, the initial material cost typically represents a sound investment, particularly for components in humid or coastal operating environments where corrosion would otherwise drive frequent repair.

Fiberglass grade selection also affects cost. E-glass is the standard, cost-effective choice used in most applications, while S-glass offers higher tensile strength and better elevated-temperature performance at a higher price. Our E-glass fiberglass buying guide outlines the properties and sourcing considerations for the most widely used grade.

Sourcing Fiberglass Materials

Silicapro manufactures and supplies a range of glass fiber materials, including woven fiberglass cloth and high silica products, to industrial clients across North America, Europe, the Middle East, and Asia. We can provide technical specifications, material data sheets, and samples for evaluation. It is important to note that materials used in certified aircraft structures must meet specific aerospace qualification requirements, so please confirm that the product specification matches both your application and the applicable regulatory framework before ordering. Contact us by email or WhatsApp using the details listed for pricing and technical support.

Frequently Asked Questions

Is fiberglass stronger than carbon fiber?

No. Carbon fiber has considerably higher tensile strength and stiffness than fiberglass, which is why it is chosen for primary structural applications where maximum performance at minimum weight is essential. Fiberglass offers a different balance of properties. It costs substantially less, is more tolerant of impact damage in some configurations, and is transparent to radio waves, which carbon fiber is not. These characteristics make fiberglass the better engineering choice for specific applications such as radomes, interior panels, and fairings, rather than a weaker substitute for carbon fiber. Both materials are used together in modern aircraft, each where its properties suit the role.

Why is fiberglass used for aircraft radomes instead of carbon fiber?

Radomes protect radar and communication antennas, and the covering must allow radio signals to pass through without attenuation. Carbon fiber is electrically conductive and would interfere with or block those signals, making it unsuitable regardless of its superior mechanical properties. Fiberglass is not conductive, so it permits radio transmission while still providing the structural strength and weather protection the component requires. This is a clear example of material selection being driven by a functional requirement rather than by strength or cost alone.

How is damage detected in fiberglass aircraft components?

Because composite laminates can sustain internal damage without visible surface indication, specialised inspection methods are required. Tap testing, in which a technician taps the surface systematically and listens for changes in sound that indicate delamination, is a common field method. Ultrasonic inspection provides more detailed subsurface information and is widely used in maintenance facilities. Thermography and other non-destructive techniques are also applied depending on the component and suspected damage type. Visual inspection alone is not considered sufficient for composite structures, which is why maintenance programmes specify defined inspection intervals and methods.

What temperature can fiberglass aircraft components withstand?

The limiting factor is the resin matrix rather than the glass fiber. Many aerospace resin systems begin losing mechanical properties around 150°C, with the precise threshold depending on the resin chemistry and cure process. At approximately 300°C and above, structural integrity of a standard laminate can be substantially compromised. The glass fiber itself withstands far higher temperatures, which is why high silica glass fiber products are used in dedicated thermal protection applications rather than as structural laminates. For any component exposed to elevated temperatures, the resin system must be selected specifically for that service condition.

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Last reviewed and updated on August 2, 2026, by Lucy Huang, High-Silica Material Specialist at Bright Sky New Material Co Ltd. (SilicaPro). This article is reviewed periodically to ensure accuracy and alignment with current industry standards.