At Tehran Imam Khomeini International Airport you come out into the arrivals hall not through an opaque set of automatic doors but down an escalator. You can see the people waiting expectantly below, watching as you descend. When I returned to Tehran last month, however, in the middle of the Covid-19 pandemic, the airport was empty. I tried to imagine the hall crowded, as it should be. Of the few people I saw, most were wearing facemasks. My suitcase had been wet when I took it off the carousel. ‘Is it raining?’ another passenger asked. Then we saw a man in a red and yellow uniform spraying the luggage with disinfectant. My journey from Toronto had lasted forty long hours, through deserted airports in North America, Europe and the Middle East. Before that I had spent fifty days alone in a deserted city where I knew no one; the only person I had known in Toronto was killed in January.

In distant, inhospitable climates, military forces often struggle to provide Close Air Support to dispersed detachments of troops on the ground. CAS involves aircraft hanging around at low altitude, close to the action, for a long period of time, to protect ground troops from such threats as enemy tanks and artillery by blowing them up. Cutting-edge fighter planes are no good for it as they quickly run out of fuel, can’t loiter long at lower altitudes and aren’t well enough armoured. The problem, which Nato is experiencing in Libya, isn’t new: the US faced it in Vietnam.

At some point in the early 1980s the father of one of my friends took a small gang of us to the Farnborough Airshow. I don't remember much about it, apart from a vague sense of the thrill of seeing the actual-size, actually flying originals of the shakily-painted plastic models of Second World War planes, pocked with dried glue, that hung from strings sellotaped to my bedroom ceiling and occasionally fell to the carpet with a feeble rip, crack and splinter in the middle of the night.