The use of Unmanned Aerial Vehicles (UAVs) for delivering various types of payloads has over the years shown many promising results, and hence, it could be argued that they can also lead to better capabilities when deployed as Airborne Early Warning (AEW) platforms. Nonetheless, the design of such specific vehicles includes many conflicting requirements that need to be balanced, and in this respect, the development team should have a suitable set of tools to capture the design space and perform tradeoff analyses. To this end, this paper presents the development of a multidisciplinary framework that can be used for the preliminary sizing and performance assessment of the potential design solutions. At the system level, the framework considers models for capturing the operation of the aircraft’s onboard systems, whereas at the aircraft level, the proposed analysis capabilities include traditional aeronautical disciplines which have been enhanced with mission-specific models. The primary aim herein is to enable a multi-fidelity analysis approach where the design space can be first analyzed with quick low-fidelity iterations, and then, the goal is to be able to extract a small number of designs in order to evaluate them in depth by using higher fidelity geometry and aerodynamic models. Overall, the possibilities of the framework and the design approach are evaluated via an exploratory case study, and finally, the paper concludes by proposing two UAV/AEW design concepts as candidate platforms for further development.