NEW YORK — Until smoldering batteries forced regulators to ground Boeing Co.’s new 787 Dreamliner jets last week, the aircraft manufacturer was flying high, with soaring profits and a recently regained number one ranking in jet deliveries over Airbus.

But the grounding, prompted by a battery fire on one jet and the emergency landing of another, has knocked Boeing off course. Investors and government officials are paying close attention to see how big the issue becomes for the company, one of the nation’s biggest exporters.