The Federal Aviation Administration said Wednesday it would no longer permit pilots or air traffic controllers to use the smoking cessation drug Chantix, citing potential side effects that could pose a threat to the safe operation of aircraft. The Food and Drug Administration issued a public health advisory in February, saying that some Chantix users had developed a variety of serious psychiatric symptoms, and that some had committed suicide. An F.A.A. spokeswoman, Laura Brown, said the agency had approved the use of Chantix for airline pilots and flight controllers last year, but was notifying 150 pilots and 30 air traffic...