This article summarizes the work of a senior design project at the Technion Aerospace Faculty aimed at designing and eventually building a small UAV for the DBF\AIAA competition. This year's competition main objective was to simulate a passenger aircraft carrying passengers or used for cargo. Initially the competition rules were carefully studied in order to determine the effect of different aircraft aspects on the score. This revealed that focusing on a single design parameter will not yield an overall higher flight score; therefore an optimization process was required between RAC and performance. The team decided to design a modular aircraft In order to simplify the building process and allowing the replacement of specific components (damaged or updated) without rebuilding the whole aircraft. The UAV designed and presented in this article has a conventional geometry of main wing and back tail. The aircraft main structure was based on carbon fiver tube, which has the highest strength to weight ratio. The payload compartments and the aerodynamic shell were built as separate structures. The specified design allowed easy aircraft loading. This year's competition includes three different missions. In each mission the aircraft will be judged by different parameters. The designed aircraft is able to fly when fully load with appro imately 2.1 g payload. The ma imum airspeed that can be achieved when flown without payloads is 24.8 m sec and the cruise speed of this configuration is 21.5 m sec.