The key innovation in this effort is the development of a decision support tool and simulation testbed for Airborne Spacing and Merging (ASM). We focus on concepts related to airports with Super Dense Operations (SDO) where new airport runway configurations, simultaneous operations on runways, simultaneous sequencing, merging de-confliction and spacing are some of the proposed concepts currently being considered. We focus on modeling and simulating a complementary airborne and ground system for ASM. From a ground systems perspective a scheduler will generate arrival sequences and spacing requirements that will be fed to the ASM system operating on the flight deck. We propose to use and enhance NASAs ACES software to model and simulate our concept. Our Phase I simulation will include a prototype model of an airport emulating SDO and an implementation of airborne spacing and merging algorithms implemented in the ACES flight agents. Integral to our proposed effort will be the understanding future demand in terminal areas as NAS transitions to NGATS type concepts and operations in 2025 including the impacts of possible VLJ induced traffic. Using the simulations we will evaluate the performance of our approach as air traffic densities increase, evaluate controller workload and investigate extensions needed for totally airborne autonomous operations.