In this proposed research and development project, we investigate and design an innovative system that solves the key problem of multi-vehicle cooperation and interoperability. Our approach is based upon the principles and techniques of Performance Based Navigation (PBN) and Required Navigation Performance (RNP) concepts and is adjusted for other separation, safety, and weather effects. We design the architecture for a system that simultaneously maintains the efficiency and success of a multi-vehicle mission while also detecting and resolving potential loss of separation and conflicts within the NAS. The challenge is that for a variety of missions, teams of unmanned vehicles can perform the mission efficiently in particular configurations, but simultaneously the team of vehicles must be aware of and accommodate themselves, external traffic, potential intruders, environmental constraints, terrain, and so forth. Our software based system, UA-Teamer, provides the architecture and solutions to achieve mission success and the efficiency promised that multi-vehicle teams can accomplish while maintaining system safety. Our primary technical objectives are: i) Demonstrate a common set of flight path planning parameters built using PBN and other constraints enabling UA to interoperate and cooperate as a team; ii) Produce an algorithmic software approach that selects a best fit flight path set for a UA team mission that involves heterogeneous UAs; and iii) Show that the planners can response to conformance monitoring needs for re-planning and contingencies. The project includes a feasibility demonstration and human factors research into the display of optional trajectory sets for the UA team.