Abstract: A checklist system comprising a computer and portable unit, according to one implementation, is described herein. The computer of the checklist system is configured to store a first portion of checklist software and one or more checklists. The computer is also configured to download checklists and software updates from a data network. The portable unit of the checklist system is configured to store a second portion of checklist software, where the second portion of checklist software is configured to operate in conjunction with the first portion of checklist software. At least one portion of the portable unit is configured to communicate with the computer in a data-sharing mode. In addition, the portable unit is configured to operate in a checklist-item-prompting mode when the at least one portion of the portable unit is removed from communication with the computer.