Companies that supply more than one off ad-hoc charters or who provide air ambulance services can be issued with either a blanket permit or verification letter. The blanket permit is a pre-paid method of obtaining an operating permit to fly into the Cayman Islands and can be issued for 3 or 6 month periods. It allows unlimited entries to the territory by the aircraft listed on the blanket permit, for the duration of the permit. A verification letter is good for a 6 month period and all flights are billed in arrears based on reconciliation with airports statistics. Each time that you intend to fly to the territory you will be required to complete the application form (Form A) listing the aircraft registration and noting that the “supporting information is on file at the CAACI” for the aircraft listed next to number 17 on the application form.