Classification	Level 1	Level 2	Level 3
1	Flight Services	Flight problems Delays	Cancellations, schedule changes, etc.
2	Ticketing Services	Ticketing Services	Overpriced tickets, failed bookings etc.
2	Ticketing Services	Over-selling problems	Double selling of seats, etc.
3	Ground service	Baggage problems	Overcharging, delayed, damaged, lost baggage, etc.
3	Ground service	Check-in problems	Security check and boarding procedures, failure to sign on, etc.
4	In-flight services	Airline problems	Unsatisfactory airline service, seating arrangements, food service, etc.
5	Other services	Cargo problems	Loss of cargo, delays, etc.
		Special services	Discrimination against special passengers, etc.
		Other problems	Advertising, SMS fraud, smoking, etc.