IEA (2020), Number of retired four-engine aircraft (scrapped or long term storage) by model and airline since March 2020, IEA, Paris https://www.iea.org/data-and-statistics/charts/number-of-retired-four-engine-aircraft-scrapped-or-long-term-storage-by-model-and-airline-since-march-2020, Licence: CC BY 4.0