Over the past century, the utilization of polymeric materials has significantly increased due to their versatility. High-performance polymers, particularly high-temperature thermoplastic polymers, have become integral to high-technology industries such as aerospace. These materials are frequently preferred over metals due to their exceptional strength-to-weight ratio, which enhances payload efficiency and reduces fuel consumption. Furthermore, thermoplastics offer several advantages over thermosets, including rapid processing and enhanced formability through techniques like additive manufacturing and injection molding. Advances in multi-scale techniques have facilitated the production of complex, high-precision components from thermoplastic polymers. Unlike thermosets, thermoplastics do not necessitate the management of chemical reactions during processing, contributing to their environmental benefits. Life cycle assessments indicate that reinforced thermoplastics have a 25% lower overall environmental impact compared to traditional thermoset compounds. Although high-temperature polymers have notable benefits, they are typically used in composite forms with reinforcing materials and suitable fillers to enhance performance and provide new properties, such as electrical and thermal conductivity. This chapter provides an introduction to high-temperature polymers, emphasizing the importance of thermoplastic composites in aerospace applications. It examines the requirements and specifications for aerospace components, introduces fiber-reinforced high-temperature thermoplastics, and analyzes different types of nanofillers used to enhance these composites. The chapter discusses the influence of nanofillers on essential properties required for aerospace applications, including mechanical strength, electrical conductivity, and thermal conductivity. It also presents an overview of the manufacturing processes for thermoplastic composites, explores the recyclability of high-temperature thermoplastic-based composites, and outlines future prospects and potential for sustainable production in aerospace. Finally, it addresses the challenges associated with high-temperature thermoplastic composites in aerospace applications.