It's difficult to argue that against the fact that China and the U.S. are increasingly becoming more important parts of each other's lives with each passing year. A good indication of the growing connections between the two nations is air travel: it's surged between the two nations over the past two decades and shows little sign of abating, as can be seen in the chart above from anna.aero, a blog on the airline industry.
According to data from the U.S. Bureau of Transportation Statistics, 2.65 million passengers took nonstop flights between the U.S. and China, a whopping 30 percent increase from the previous year. Despite minor dips in U.S.-China air traffic following 9/11 and again during the late-2000s recession, the trend of increased travel between the two since 1990 is quite clear, and should be interrupted as a sign of the proliferation of business between the established superpower and the emerging one. It should be noted, though, that U.S.-China air traffic is dwarfed by that between the U.S. and other countries with which trade relations are more thoroughly established. In 2010, 10.8 million people flew between the U.S. and Japan and 15.8 million flew between the U.S. and the U.K. The anna.aero blog post notes, though, that air travel between the U.S. and China is highly regulated by agencies on both sides of the Pacific, so the relatively low U.S.-China figure may not be due to lack of demand. In any case, expect to see this figure climb even higher in the near future.