Powering through the scrum in a green tunic, 17-year-old Zaki Anwari made his way to the front and clambered onto the plane’s landing gear. As it accelerated past 120 miles an hour, he held tight.

Hours earlier, as the Taliban began its first morning in charge of Kabul, Mr. Anwari, a high-school senior and attacking midfielder for the national youth soccer team, phoned his brother to tell him that if he didn’t flee Afghanistan he would never play again.

“Do not go, go back, you are smart, don’t go,” his elder brother Zakir said.

“I have to try,” Mr. Anwari replied…

All were members of a generation of Afghans who haven’t known rule by the Taliban and were terrified enough to grab hold of an accelerating military jet if it meant a ticket out.

“It was not just the fall of Kabul. It was the fall of a whole new generation who believed and worked for progressive Afghanistan,” Shafiqa Khpalwak, a Kabul-based poet, wrote on Twitter. “Trusted the world. And hoped for a brighter future.”