**1.1 Background**

Affected by the COVID-19 epidemic, passenger travel demand has declined sharply, various countries' strict immigration management policies have pressed the pause button on cross-border travel, and the global aviation market has entered a

freezing period. Since the outbreak of the COVID-19, the development of the global civil aviation industry has been dramatically impacted. Statistics from the Civil Aviation Administration show that the total number of passenger flights performed by domestic airlines in China in 2020 decreased by about 22% compared with 2019 [1]. In the information age, it is imperative for airlines to adjust their market strategies according to the changes in the market under the epidemic, deeply cultivate market segments, and form a differentiated competitive advantage. The differentiated service of customers is the key to the differentiated competition of airlines, and it is also the core of the airline's implementation of digital strategy. Through customer classification, we can distinguish between worthless customers and high-value customers to formulate optimized, personalized service plans for customers with different values, adopt different marketing strategies, concentrate limited marketing resources on high-value customers, and achieve the goal of maximizing corporate profits [2]. In the case of ensuring data security, accurately identifying customer categories is an essential means for enterprises to optimize the allocation of marketing resources.
