I'd say it depends a bit on the type of interview. I would not see this as a full-blown case, but it might be employed for a simplified interview process, e.g. for one of the business courses for students. To participate there, you'll need to apply and pass an interview, but it's typically a 30min interview with a junior consultant, rather than a series of several interviews with more senior people.

You could deploy a standard strategy framework like the other coaches suggested. For this simplified interview, it might even be enough to demonstrate you business judgement. Talk about general business drivers like

• Competitive pressure: Airlines offer a commoditized product (getting you from A to B), while biotech companies develop specific drugs and technologies that might not compete with each other directly.
• Differentiation: The only way for airlines to differentiate is on non-essential services and maybe loyalty cards, but the core service is completely commoditized.
• Price awareness: Customers that purchase a flight might be looking to do so at the lowest price, while customer that purchase potentially life saving drugs to care about money.
• Price transparency: You can compare prices for different flights within seconds on your mobile, getting price quotes from different drug manufacturers is much more difficult.

My bottom line is: For these type of cases you might not need a super fitting framework, if you're quick on your feet and can talk about 2-3 key reasons that actually make sense on the fly. If this should be part of a larger case however, I fully agree: You'll need a strong framework upfront.