Wavelet-Based Investigation of AIr-Passenger Transport Linkages in Asian Emerging Economies: Implications for Environmental Management and Economic Sustainability

This study investigates the time-varying spectral coherence of air-transportation in several Asian emerging economies (i.e. Indonesia, India, Iran, Malaysia, Pakistan, Singapore, Sri Lanka, Turkey, Korea, and Japan) focusing on the environmental economic implications. Employing a quantitative, time-series approach, and the study analyzes dynamic interdependencies within air-transportation data that are critical for environmental management and sustainable economic development. The dataset comprises sixty years of country-level air-transportation statistics sourced from the World Development Indicators, providing a comprehensive temporal perspective. Methodologically, wavelet analysis is utilized alongside descriptive statistics to uncover multi-scale patterns, using time-series graphs, individual and cross-wavelet power spectra, and wavelet coherence metrics, with special emphasis on Pakistan's linkage with other nations. Plots of air-passengers carried show a steady increase in numbers across all countries, led by Japan and Pakistan (notably in 2009/2010), and followed by a sharp rise until 2019. Individual wavelet power spectra reveal weak correlations at low frequencies, moderate to high correlations at middle frequencies, and strong correlations at high frequencies. Cross-wavelet spectra indicate weak co-movement at low frequencies, moderately strong co-movement at middle frequencies, and consistently high co-movement at high frequencies over the sample period. Wavelet coherence spectra display high coherence at low frequencies, mixed patterns at middle frequencies, and weak correlations at high frequencies, with noted edge effects between 2010 and 2019 at high frequency bands. Time-frequency results are broadly consistent, with certain bands showing higher coherence and correlation, confirming phase synchronization in the regions. This research offers novel insights into the environmental and economic sustainability of air-transport networks by applying advanced spectral techniques to emerging Asian markets. The findings provide valuable guidance for policymakers and industry stakeholders in designing regional environmental strategies and coordinating economic policies that balance the growth with ecological resilience in the air-transport sector.