Apple’s iPhone Air sold out within minutes of its launch in China on Friday, underscoring the device’s popularity among Chinese consumers despite competition from Android devices. The strong sales followed CEO Tim Cook’s visit this week to promote the product in the world’s largest smartphone market amid ongoing geopolitical tensions between China and the US. As chairman of an advisory body at Tsinghua University’s management school, Cook also met Vice-Premier He Lifeng on Thursday. Pre-sales...