American factories are running short of parts.

A truck driver for the Schwebel Baking Co. rolled out of Cleveland toward Rochester, N.Y., on a recent day with a trailer full of freshly-made sandwich rolls and buns. Less than an hour into the run, sensors tied to his tractor-trailer started sending a stream of urgent data messages that led the big rig to turn around and head back to the bakery.

Cargo streamed into U.S. seaports at a rapid rate in June, as businesses pulled in goods in an apparent rush to stock up ahead of new tit-for-tat tariffs between the U.S. and China.

Boeing Co. and Airbus, swamped with orders for new jets, are struggling to deliver them all on time — in some cases angering customers and delaying payments.

For U.S. retailers, manufacturers, importers and exporters, warehouse space is at its tightest since 2000, when the first dot-com boom was driving strong consumer spending and imports from China were beginning to surge.