1. Advisory Council for Aeronautics Research in Europe (ACARE)https://www.acare4europe.org/sria/flightpath-2050-goals/protecting-environment-and-energy-supply-0
2. Global Market Forecast 2019–2038 Airbus Commercial Aircraft Bookhttps://www.airbus.com/content/dam/corporate-topics/strategy/global-market-forecast/GMF-2019-2038-Airbus-Commercial-Aircraft-book.pdf
3. Effects of COVID-19 on Civil Aviation: Economic Impact Analysishttps://www.icao.int/sustainability/Documents/COVID-19/ICAO_Coronavirus_Econ_Impact.pdf
4. Airbus Plans to Further Adapt to COVID-19 Environmenthttps://www.airbus.com/newsroom/press-releases/en/2020/06/airbus-plans-to-further-adapt-to-covid19-environment.html
5. Boeing Forecasts Challenging Near-Term Aerospace Market with Resilience in Long Termhttps://boeing.mediaroom.com/2020-10-06-Boeing-Forecasts-Challenging-Near-Term-Aerospace-Market-with-Resilience-in-Long-Term