Flight chaos shows mixed response

As more countries placed travel bans on southern Africa early Saturday, the passengers on two flights from South Africa found themselves caught in a nightmare in Amsterdam.

After about 30 hours squeezed together in the planes, crammed buses and then in waiting rooms, 61 of the more than 500 passengers on those flights had tested positive for coronavirus and been quarantined. They were being checked for Omicron, named by the World Health Organization on Friday as a “variant of concern,” its most serious category.

The chaos in Amsterdam seemed emblematic of the varied, and often scattershot, responses to the virus across the world, with differing masking rules, national testing requirements and vaccine mandates. (KLM, the airline operating the flights, said only some passengers had to show proof of a recent negative test, depending on vaccination status and the requirements of their final destination.)