Airplane maker Boeing says it has discovered manufacturing defects in its 787 Dreamliner and has called for the inspection of 43 jetliners. Boeing announced the discovery of the manufacturing defect by Japanese wing-maker Mitsubishi Heavy Industries on Friday, the Seattle Times reported. The 43 jets, which have not yet been delivered to airlines, will be inspected for small hairline cracks inside the wings. Boeing spokesman Marc Birtel said the inspections and any fixes that need to be made will take one to two weeks for each airplane. "While there may be some delays to deliveries, we are confident that we are doing what must be done," Birtel said. "We understand the issue, what must be done to correct it, and are completing inspections of potentially affected airplanes." Mitsubishi said in a statement that it reported the cracks to Boeing and was working to determine the cause at its facilities, the Wall Street Journal reported. A spokesman for the Federal Aviation Administration said it would work with Boeing to "ensure that the issue is corrected before the airplanes are delivered." Boeing said it still plans to deliver 110 Dreamliners this year.