Now, travelers have questions about whether or not it is safe to fly on Boeing's 787 Dreamliner plane. (According to aviation analytics firm Cirium, there are 1,148 Boeing 787s in service worldwide.)

Last year, the F.A.A. said it was also investigating claims by a Boeing engineer that parts of the fuselage, or body, of the Dreamliner were improperly fastened together, which the whistle-blower said could cause premature damage to the plane over years of use.