BEIJING—Airports at Xian, Hangzhou and Guangzhou were the fastest growing among China’s top 10 in 2017, according to data from the Civil Aviation Administration of China (CAAC). Double-digit growth by Guangzhou Baiyun International Airport is perhaps most remarkable, since the facility is already the third-busiest in China. Such growth rates, once common, are now more rarely seen among the largest airports, as their runways and airways have become full with ...