Hi Surendranath,
Six Sigma can be applied to any organization which depends on processes.Aviation is hugely processed dependent and error tolerance for 90 percent of the processes stands at zero.Keeping that in mind a few application areas for Six Sigma in aviation would be
TAT calculation for turnaround flights.
Waiting time at the check-in counters, Ticketing counters, Security checks can be observed and SPC can be applied to control these critical to time processes.
TAT for cargo+baggage loading and offloading.
TAT for catering loading and offloading
These are the few representative areas where we can implement six sigma. However to implement a six sigma process improvement project data collection would be of paramount importance.Make sure you have a strong data collection strategy before you jump start.
Hope this helps for now.
Mainak kanjilal