I write this in the Singapore Airlines lounge at Heathrow. My flight doesn’t leave for another three hours, but these are, to put it mildly, uncertain times: my daughter, who flew out from London to Washington yesterday, texted me from her gate to warn me that in their determination to check the export of coronavirus across the Atlantic, United have augmented the airport’s normally stringent security checks with their own compulsory hand sanitation protocol and the application of thermometers to foreheads.