The COVID-19 pandemic negatively affected and caused considerable changes in the aviation industry. This study determined the difference in the monthly percentage of flight delays before and during the pandemic, including United, Delta, and American Airlines. The results showed the percentage of average flight delays was higher for the pre-pandemic period.
Gonzalez Fuentes, Orlando Y.; Lee, Chinkyung; Lee, Hyungyeong; and Wheeler, Brooke, "Legacy Airlines’ Monthly Percentage Delays: Before and During the COVID-19 Pandemic" (2022). Aeronautics Student Publications. 7.