Analysis of Area Navigation (RNAV) arrival flights at Las Vegas airport, in the form of operational data analysis and simulation modeling, has shown improvements in flight efficiency. A redesign of flight paths in Las Vegas airspace has confounded a pure RNAV vs. non-RNAV comparison, but statistical analysis has allowed a partitioning of effects. Analysis of metrics such as altitude, flight time variation, arrival interval, and flight time and distance will provide insight into the increase in flight efficiency possible with RNAV. MITRE CAASD performed several analyses concerning benefits of RNAV arrival procedures in the terminal area, incorporating both simulation modeling and data analysis into the project. Initial results for Las Vegas show promise toward the full RNAV vision.