The development of airport alliances has undergone hardships, although airport alliances have emerged simultaneously with other airline alliances in an attempt to improve competitiveness. Technology spillover is a major benefit of airport alliances, but the effects of such spillover are not as obvious as might be expected. This paper proposes a three-stage DEA-based methodological framework to uncover the existence and characteristics of technology spillover among allied airports, and identify whether the technology spillover of airport alliances outperforms the self-development of airports. A case study that concerns multi-airport companies and non-allied airports in China, where airports and airlines are rapidly expanding, is included. The results show that the technology spillover of airport alliances does not become wide spread among all of the allied airports, which is most likely because civil aviation in China is still in a stage of rapid development. However, such spillover does appear among small- and mid-sized allied airports in cities with fast urban economic development. Finally, the related implications of our methodological framework are discussed along with our findings.