Northrop Grumman, the fifth-largest U.S. defense contractor, today announced it had signed an agreement to acquire Navia Aviation AS, an operating unit of Navia ASA of Oslo, Norway. Northrop Grumman said in a statement that it would pay $35 million in cash for the Norwegian instrument landing systems supplier, and the company expects to close the deal by the end of the calendar year. In addition to instrument landing systems, Navia AS makes digital voice switching systems and air traffic...