For your safety, this is more or less what should be done, yes. In practice, they follow AIR OPS regulations set by the FAA or EASA, with fairly up-to date wei

For your safety, this is more or less what should be done, yes. In practice, they follow AIR OPS regulations set by the FAA or EASA, with fairly up-to date weight studies to estimate the average passenger weight. So for your example, if you use the data average obtained for Europeans, you will be, on average, safe when flying Kenyans and North Koreans. Here is a link to the latest EASA weight study: https://www.easa.europa.eu/en/document-library/research-reports/easa2021c24 https://www.easa.europa.eu/en/document-library/research-repo...