The head of the Federal Aviation Administration, who has led a tougher enforcement policy against Boeing since a panel blew off a Boeing jet in January, will step down next month to let President-elect Donald Trump name his choice to lead the agency. Mike Whitaker announced his pending resignation in a message to FAA employees Thursday. Whitaker has dealt with challenges including a surge in close calls between planes, a shortage of air traffic controllers and antiquated equipment at a time when air travel, and a need for tougher oversight of Boeing.