SEATTLE/CHICAGO, June 3 (Reuters) - Boeing Co Chief Executive Dave Calhoun on Thursday pointed to potential “supply constraints” beginning in the summer after a “more robust” recovery from the coronavirus-related downturn than he had imagined. Speaking at a Bernstein virtual conference, Calhoun also said he expects Boeing will be able to deliver the “lion’s share” of roughly 100 787 aircraft sitting in inventory due to production defects and weakened demand. With U.S. leisure travel going “gangbusters” and carriers needing to rehire and rebuild their networks and supply chains, Calhoun said, pointing to likely “supply constraints for a while.” Reporting by Eric M. Johnson in Seattle and Tracy Rucinski in Chicago; Editing by Leslie Adler Our Standards: The Thomson Reuters Trust Principles.