The essential entries required on airline sales returns are ticket number, fares charged, and form of payment; with these, all ticket numbers and airline coupons should be entered and attached. If no ticket is issued in any month, a “no sales” report must be sent to the airlines whose ticket stocks are held by the agency. The final airline sales returns should be verified and approved by the bookkeeper to ensure that the relevant ticket payment information is correct. In accordance with IATA regulations, the total net amount of the return is usually payable to the airline not later than the 15th of the month.