Energy shortage is exacerbated by energy wastage and low efficiency, so energy efficiency has become a popular research topic. However, in most studies, the inputs and outputs of energy efficiency are selected through qualitative analysis and literature review, the rationality is not convincing....

In this paper, the energy efficiency of airlines has been studied with number of employees, capital stock and tons of aviation kerosene as the inputs and Revenue Ton Kilometers, Revenue Passenger Kilometers, total business income and CO2 emissions decrease index as the outputs. A new model,...