Barbara Pijanowska-Kuras confirmed that a flight to Chicago was canceled on Wednesday because of problems with the power system, while another to Toronto was postponed because of issues associated with the plane's tracking system.
She said the problems were minor and not linked to the battery problems behind the global grounding of the 787 fleet earlier this year.
The Toronto flight took off Thursday morning after the problem was fixed, while the other plane was still undergoing checks on Thursday and passengers were put on other flights, she said.
LOT has four 787s and was the first European airline to buy the plane, dubbed The Dreamliner by Boeing.
All four are making dozens of long-haul flights each week to New York, Chicago, Toronto and Beijing, Pijanowska-Kuras said.
However, the plane has proved something of a headache for the cash-strapped company, which is currently going through a restructuring that involves layoffs.
LOT is in talks with Boeing over how much it should be compensated for the grounding of the world's fleet.