NON REFUNDABLE TICKETS- some tickets issued by the airliner are just non refundable. Anyhow, you can get a credit voucher which can be used in future.
REFUNDABLE TICKETS- you are eligible for a refund only if you had procured the refundable tickets. However, some cancellation fee or processing fee may incur. Cancel fee may depend upon the route and type of flight and varies in between $75 to 200
TIMING- cancellation requests within 24 hrs of booking will enjoy a full refund. Cancellations exceeding the time limit of 24 hrs may face a nominal processing charge which is variable.
IMPORTANT – flights cancelled by the airlines itself, cancellations due to medical emergencies and duty calls of deference personnel are exempt from the formalities of the cancellation policy. only you have to produce the concerned document.