Earhart places preparation at the centre of any demanding undertaking. Her reference to “two-thirds” is not a literal calculation, but a way of emphasising how much successful action depends on work completed before the main event begins. In aviation, this includes studying routes, assessing weather, checking equipment and anticipating possible difficulties.

The principle extends beyond flying. Careful preparation can identify risks, clarify objectives and reduce the number of decisions that must be made under pressure. It cannot guarantee success, because circumstances may still change and execution remains necessary, but it improves the conditions in which action takes place. The quote therefore presents preparation as an active part of a venture rather than merely a preliminary stage. Its broader message is that achievement often depends as much on disciplined planning and readiness as on the visible moment of performance.