Lockheed Martin Corp is using its own funds to pay suppliers and stave off the closure of its F-16 fighter jet production line as it waits to finalize orders from Pakistan and other countries, a company official said on Tuesday.Orlando Carvalho, who heads Lockheed's Aeronautics division, said the cost of keeping the F-16 supply chain ready for further orders was "very manageable," but did not elaborate. Lockheed is now funding suppliers to ensure it will be able to build planes for Pakistan and other countries after it wraps up work on 36 F-16 jets ordered by Iraq in 2017.Congress and the U.S. State Department are in talks about funding for a $700 million sale of eight F-16 fighter jets to Pakistan that were approved by Congress last week.