HOUSTON (AP) — Houston Airport System officials are working toward a $1.5 billion project to rebuild and expand the international terminal at Houston's George Bush Intercontinental Airport. System Director Mario Diaz says the project to overhaul Terminal D — also known as the Mickey Leland International Terminal — is vital to maintaining Houston as an international hub for United Airlines. He says the trick is to keep the terminal operating even as it's totally rebuilt — a process officials say could take up six years to complete.Read more on NewsOK.com