I work for a large corporation. We have an in-house travel department and all flights, rooms and cars are booked through them, with few exceptions, online. We have "preferred" vendors in all 3 categories and earn discounts & rebates with them. Those concessions are volume dependent, and we are encouraged to follow the recommendations even in cases where an individual trip looks like it may cost more than if we were using alternative carriers/properties. Our annual savings are in the millions of dollars. If we all made completely independent travel decisions, that might not be the case. It's a team effort, and sometimes you're called on to bunt. There are methods to get around specific preferred carriers and I will be happy to share some hints (it's not rocket science) after you have landed the job. It should still be possible to maximize miles, points and status while staying within bounds. Meanwhile, you're still trying out for the team. It might be appropriate to discuss it during a light moment on interview day, maybe over lunch, but don't think about showing them how much smarter you are than their travel department/agent.