Composites are becoming increasingly important in the aerospace industry. At least 30-40 per cent of modern airframes are now made of composites, and this percentage is increasing rapidly due to technological advances in the field. The use of composites for primary structures such as fuselages and wings has grown significantly in transport aircraft. This white paper examines the challenges and advantages of using composites in airframe manufacture, as opposed to aluminium and other alloys such as aluminium-lithium.