When my son Alyosha was little, I promised myself that I would show him the world. To this end, I saved my pennies and took him far and wide – to the Costa Rican rainforest, the geysers and glaciers of Iceland, the pristine beaches of the Caribbean, and the grand cities of Europe. With his red-and-blue backpack bobbing, he was an uncomplaining and companionable traveler, adapting to foreign cuisines, different languages, and the cancellations and delays that are part and parcel of traveling by air.

Since I was the adult, it was, of course, my responsibility to plan things out as carefully as possible: luggage, plane tickets, accommodations, currency exchange, public transportation, and our itineraries. In short, I was the leader, and Alyosha’s job was to step lively and follow in my carefully planned wake.…