Devices powered by lithium-ion batteries are overheating more often during airline flights and passengers often put them in checked bags that go into the cargo hold, where a fire might not be detected as quickly. Overheating incidents rose 28% from 2019 to 2023, although such events remain relatively rare, UL Standards said in a report released Monday. In 60% of the cases, the overheating — called thermal runaway — happened near the seat of the passenger who brought the device on board.