What constitutes eligible flights for earning Companion Pass?

The criteria for earning a Companion Pass with Southwest Airlines are specifically centered around the completion of 100 qualifying one-way flights or the accumulation of 125,000 qualifying points within a designated timeframe, typically a calendar year. This option is correct because it directly aligns with Southwest's requirements for allowing a Companion Pass holder to designate a travel companion who can fly for free on the same flights, subject to availability.

The other choices do not accurately reflect the eligibility for earning the Companion Pass. For instance, flights booked with third-party vendors do not contribute to the qualification process. Furthermore, not all purchased tickets meet the qualification criteria, as there are specific requirements regarding the types of fares and flights that qualify. Likewise, limiting the eligibility to international flights does not encompass the full spectrum of flights eligible for earning a Companion Pass, as both domestic and international flights can count toward the qualifying total.