Unmanned Aerial Vehicles (UAVs) have been drawing significant attention as effective tools for observing disasters, especially in the context of large-scale disasters, where the establishment of seamless communication channels becomes imperative for verifying safety details and assessing the extent of the disaster. In most instances, insufficient UAV inventories make collaborative efforts among UAVs indispensable for enabling rapid and long-distance data transmission. This paper introduces a UAV data collection model designed for relay transmission of observed data through multi-hop relay communication. It also explores the freshness of data delivery, quantified using the recently developed Age of Information (AoI). Additionally, we derive the formula for calculating AoI and propose a UAV flight scheduling strategy aimed at enhancing the long-term average instantaneous AoI. We demonstrate the performance benefits of this strategy in terms of AoI, average duration, and energy consumption under the proposed framework through a comparison with traditional strategies.