Refer to Chapter $2,$ "Aviation Metrics," in Quantitative Methods in Aviation Management textbook. Review the definitions and significance of the following key aviation metrics: Available Seat Kilometers $($ASK$),$ Passengers Carried $($PAX$),$ Revenue Passenger Kilometers $($RPK$),$ and On$-$time Performance $($OTP$).$ Provide a concise summary of each metric, explaining its role in measuring airline performance.