As the busy holiday travel season arrives, so too does the infrequent flyer. That means a very particular secondhand market is about to start booming, one that depends on people who, more than a decade after the Sept. 11 attacks, still do not know that you cannot carry a machete onto an airplane. Or a baseball bat. Or scissors. Or hammers. Or . . . you wouldn’t believe it all. (bostonglobe.com) More...