IFAR 2025 Perspectives on Noise Reduction for Emerging and Conventional Air Transport

Kurzfassung

Aircraft noise remains a major constraint on the growth and societal acceptance of air transport, despite an overall reduction of about 75% in noise levels since the 1960s achieved through successive generations of quieter engines and airframes. This paper, developed from the discussions held during the 2025 IFAR (International Forum for Aviation Research) Summit, reviews technological and regulatory trends aimed at enabling "quieter aviation" for both large commercial aircraft and emerging operations such as Advanced Air Mobility (AAM) and future supersonic transport. The analysis brings together expert insights on propulsion and airframe noise-reduction technologies, advanced acoustic liner concepts, and morphing airframe concepts, alongside regulatory, operational, and economic measures designed to reduce noise immission around airports. Some forty senior researchers from twenty national research institutions across the IFAR network contributed to the discussions in Vienna in October 2025. Particular attention was devoted to the growing role of artificial intelligence (AI) in noise prediction, community response modelling, and trajectory optimization, as well as to the specific challenges associated with urban AAM noise and the acceptability of supersonic sonic booms. The paper concludes by outlining priority research needs and strategies that jointly address technological maturity, certification pathways, and the socio-political acceptance of future low-noise aviation systems.