Passage Summary: Swift Airlines canceled nine flights in one day. Because it's very unusual for many planes to break down at the same time, the airline probably had other reasons for some of those cancellations.

Conclusion: Some of the nine flight cancellations were likely caused by factors other than mechanical issues.

Reasoning: While mechanical problems usually cause cancellations, it is rare for a single airline to experience more than one or two such problems in a single day.

Analysis: The argument assumes a direct, limited relationship between a mechanical failure and a cancellation. Specifically, it relies on the idea that one mechanical problem doesn't typically lead to a cascade of multiple cancellations. If a single broken engine on one plane could cause five different scheduled flights to be grounded throughout the day, the author's numerical evidence loses its punch. Look for an answer that addresses whether a single mechanical issue can account for more than one cancellation.