By Justin Bachman, Bloomberg After a routine flight Friday from Houston to Colorado Springs, a United Express regional jet began heading northwest. Way, way northwest. It flew all the way to China, making many stops along the way. The regional jet’s far-flung destinations caught the attention of aviation enthusiasts and led to speculation on Twitter. It turns out the plane’s manufacturer, Embraer SA, is leasing the 76-seat E175 as a demonstration for a prospective Chinese customer. United Continental Holdings Inc.