Triumvirate of Terror! - S3-E8
Plot hole: After Superman thwarts Lex's plan and knocks the Kryptonite into the sewers, Lex yells in frustration, splits his power suit off and flies away on a jet pack. Superman just lets him go. Wouldn't Superman chase him and catch him, especially seeing as how weak Lex would be like that? (00:07:35)