FedEx Corp. executives said fears over the escalating trade fight between China and the U.S. are starting to hurt economic activity between the two countries.

The tariffs implemented so far have hit about 10% of FedEx’s business in China, where the carrier generates about 2% of overall revenue. But uncertainty over further actions, including an expected round of additional U.S. tariffs on $200 billion worth of Chinese imports and how Beijing retaliates, is creating jitters and resulting in a slowdown in economic activity,...