Spirit Airlines is an unusual airline; although often cited as the most hated airline in the US$,$ it is also one of the fastest growing airlines in the world. How is that possible? Spirit competes as an ultra$-$low cost carrier $($ULCC$),$ and does so by unbundling extra services from its basic fare. As a result, things that other airlines include in their prices $($for example, carry$-$on bags$)$ cost extra on a Spirit flight. This approach allows Spirit Airlines to keep prices low, attracting a different type of customer who values price above comfort and amenities. Spirit$$s low price is a key strength of its strategy; a key weakness is that many first$-$time customers do not understand, and are therefore surprised and angered by$,$ this unbundling strategy when they arrive at the airport and find that additional fees are due for services they typically receive at no cost$.$

Questions:

What are the strengths, weaknesses, opportunities, and threats resulting from Spirit$$s $$Bare Fare$$ strategy?

Of the three bases of sustainable competitive advantage, which one does Spirit appear to be pursuing? What else must Spirit Airlines do$,$ besides providing ultra$-$low fares, to achieve this type of sustainable advantage over its competitors?