低空交通运输是低空经济面向交通运输行业落地转化的核心应用场景，也是综合交通由平面网络向立体网络跃迁的重要增量。本文在系统梳理国内外发展实践与共性特征基础上，对低空交通运输理论演进的阶段划分及其内在逻辑进行分析，厘清了低空交通运输的概念内涵与构成要素，概括其立体性、融合性、创新性与经济性等属性特征，明确其作为综合交通运输体系新组成部分、行业转型发展新技术路径与产业升级新方向的功能定位。在此基础上， 揭示低空交通运输与综合交通运输的互动机理。面向完善现代化综合立体交通网与培育交通运输领域新质生产力，本文从陆空协同的视角，构建了以“设施协同、管理协同、服务协同、产业协同”为核心的四维推进路径，并提出强化安全保障、深化统筹融合、坚持场景牵引、培育产业生态、夯实人才支撑与推进试点示范等对策建议，旨在为我国低空交通运输政策制定、理论深化与产业实践提供参考。

Low-altitude transportation is the core application scenario for the transformation of low-altitude economy to the transportation industry, and it is also an important increment for the transition of comprehensive transportation from plane network to three-dimensional network. Through a systematic review and comparative analysis of the development practice and common characteristics at home and abroad, this paper analyzes the stage division and internal logic of the evolution of low-altitude transportation theory, clarifies the concept connotation and constituent elements of low-altitude transportation, summarizes its three-dimensional, integration, innovation and economy and other attribute characteristics, and defines its functional positioning as a new component of the comprehensive transportation system, a novel technological pathway for industry transformation, an emerging direction for industrial upgrading. On this basis, the interaction mechanism between low-altitude transportation and comprehensive transportation is revealed. Guided by the objective of enhancing the modern integrated transportation system and oriented toward cultivating new quality productive forces in the transportation sector, this research adopts an air-ground coordination perspective to construct a four-dimensional advancement framework centered on "facility coordination, management coordination, service coordination, and industrial coordination". Furthermore, it puts forward systematic policy recommendations focusing on strengthening safety guarantees, deepening integrated planning, maintaining scenario-driven development, fostering industrial ecosystems, solidifying talent support, and promoting pilot demonstration. The aim is to provide reference for policy formulation, theoretical advancement, and industrial practice in the field of low-altitude transportation in China.