Keep a wary eye out next time you’re aboard a Boeing 787 Dreamliner. Hairline fractures have been discovered on the wings of at least 42 brand new jets, which haven’t been delivered from the manufacturer to buyers yet. A Boeing spokesman said the problem will take one or two weeks to fix but 17 of the 42 planes have already been repaired. They will undergo tests before they’re delivered. It’s not the first time the 787 Dreamliner has gone through problems. A failed electrical generator caused including an emergency landing in New Orleans in December 2012 and in January 2013, reports spread of batteries catching fire on the planes.