U.S. automakers and other manufacturers that rely on imported components also would be affected by the proposals, which would tax imports at a 20 percent rate, and could split these sectors into winners and losers.
The revamp would heighten existing tensions in the aerospace industry, where Boeing's aggressive cost-cutting driven by fierce competition with European rival Airbus has pushed suppliers to lower prices and source more parts and materials abroad.
Aerospace components often zigzag through multiple countries and companies before reaching Boeing's factories in Washington and South Carolina. U.S.-based suppliers to Boeing would face a tax on their imports of these parts. Boeing, the top exporter among U.S. manufacturers, would export its jetliners tax free.
Boeing and some of its largest suppliers, such as United Technologies Corp, General Electric Co and Honeywell International Inc, which also have substantial exports, favor the Republican tax package.
