AUSTIN- Austin Aero Jet Center has signed a 40-year lease for 70 acres on the new Austin Bergstrom International Airport, which is scheduled to open next May. Construction is underway for an FBO and 65,000-square-foot hangar. The terminal will be a two-story building made of glass, limestone and stucco. The interior will consist of granite and marble. The facility is scheduled for completion next April. The Jet Center will be open 24 hours a day, and will offer maintenance, aircraft cleaning, fuel and hangar space.