With the development of new‒type power systems and the low-altitude economy, the scope of source‒load coordination is gradually expanding from electric vehicles to low-altitude electric terminals and their supporting energy-replenishment facilities. Accordingly, the participating entities, spatial boundaries, and coordination mechanisms are also being extended. Against this background, this study investigates vehicle‒aerial mobility‒grid (VAMG) interaction as an emerging form of source‒load interaction. It defines the fundamental concept of VAMG interaction, analyzes the differences between electric vehicles and low-altitude aircraft in terms of mission types, time scales, spatial characteristics, and operational constraints, and compares the energy characteristics of these two resource types. Moreover, the study analyzes the evolutionary logic from vehicle-to-grid (V2G) to VAMG interaction and multidimensional values of VAMG interaction. Meanwhile, the flexibility potential of low-altitude aircraft participating in source‒load interaction is quantitatively evaluated using typical application scenarios of logistics unmanned aerial vehicles as examples. Three typical VAMG scenarios are identified: shared energy-replenishment infrastructure, air‒ground collaborative missions, and emergency support. Key technologies are summarized in terms of transparent state sensing, energy replenishment control of heterogeneous ground and aerial terminals, coordinated planning for the grid integration of low-altitude nodes, and multi-timescale energy-flow optimization and scheduling. The evolutionary pathway from the existing V2G business model toward a composite VAMG model is also discussed. The analysis suggests that VAMG interaction remains in transition from conceptual validation to engineering demonstration. Further commercialization and industrial deployment require improvements in standards systems, grid-access rules, market mechanisms, industrial coordination, and policy guidance. With these supporting measures in place, VAMG interaction is expected to become an important form of transport‒energy integration, offering new pathways for enhancing grid flexibility, transportation efficiency, and urban resilience.