Tools designed to increase the efficiency of air traffic control systems must handle increases in air traffic volume, complex aircraft types and business models, and variations in aircraft performance. A comprehensive Metroplex planning system would help coordinate flights en route to Metroplex domains, schedule outgoing flights, and manage surface traffic, using Next Generation Air Transportation System (NEXTGEN) concepts. IAI's MetroSim is an innovative Metroplex-based arrival, departure, and surface optimization system that seamlessly links with NASA’s Traffic Management Advisor (TMA) toolkit, the FAA-proposed Terminal Flight Data Management (TFDM) system, and with databases of live or recorded flight data. MetroSim allows air traffic controllers, traffic flow management experts, airline dispatchers, and pilots to feel more certain in operations planning, recover quickly from disruptive events, maintain high throughput in adverse weather conditions, and handle uncertainties associated with irregular operations. MetroSim performs scheduling simultaneously, using a suite of tools that interact in a distributed environment, requiring minimal data sharing, and no centralized database. MetroSim's flexible architecture allows it to be adapted to any Metroplex. IAI has produced a prototype MetroSim system that considers all arrivals, departures, and surface operations at the New York Metroplex (N90) when determining a recommended schedule for controllers. In static tests, the system has shown promise in achieving a 5% to 20% increase in throughput over recorded data. Next, the MetroSim prototype will be connected to NASA’s SMART-NAS system to enable performing tests with live data. MetroSim will be available as a scheduling asset that can be used by other applications of SMART-NAS.