A Boeing jet earmarked for China was returning to the United States on Friday, flight tracking data showed, as the planemaker's flagship delivery plant outside Shanghai was drawn into a deepening tariff war between Beijing and Washington.

For aerospace, Zhoushan is the latest staging post in a growing U.S.-led trade war. Planemakers, airlines and suppliers are reviewing contracts after Reuters reported that U.S. supplier Howmet Aerospace had ignited a debate over the cost of tariffs by declaring a "force majeure event".