Washington (CNN) -- The U.S. military cleared the F-35 fighter jet to fly again after the fleet of jets were temporarily grounded. The jets, that are designed for use by the Navy, Air Force and Marines, were grounded on February 21 due to a crack in an engine component that was discovered during a routine inspection in California, the Pentagon said. On Thursday, military officials said engineers had analyzed the jets and cleared them. "No additional cracks were found during inspections," the Pentagon's F-35 program office said in a statement. "This decision concludes a cautionary flight suspension." The nearly $400 billion Joint Strike Fighter is the Pentagon's most expensive weapons system. The program has been beset by cost overruns and various technical problems during development. Currently, there are 51 planes in the F-35 fleet.
The jets were grounded on February 21 . On Thursday, military officials said engineers had analyzed them . The nearly $400 billion fleet is the Pentagon's most expensive weapons system .