1. Intergovernmental Panel on Climate Change (IPCC): Summary for Policymakers
https://www.ipcc.ch/site/assets/uploads/sites/2/2019/05/SR15_SPM_version_report_LR.pdf
2. Advisory Council for Aeronautics Research in Europe (ACARE)
https://www.acare4europe.org/sria/flightpath-2050-goals/protecting-environment-and-energy-supply-0
3. Airbus Environment
https://www.airbus.com/content/dam/corporate-topics/corporate-social-responsibility/environment/Environment-matters-for-the-future-of-aerospace.pdf
4. Boeing Environment Report
http://www.boeing.com/resources/boeingdotcom/principles/environment/pdf/er-companion-summary-092820.pdf
5. Effects of COVID-19 on Civil Aviation: Economic Impact. Analysis
https://www.icao.int/sustainability/Documents/COVID-19/ICAO_Coronavirus_Econ_Impact.pdf