Aetna overall is too large to generalize, and I was hired a long time ago (just laid off). They seek to pay people for results over performance and effort, however. There are behavioral interview questions available for review and use by hiring managers, but they may also revise these or draft their own. Aetna used to be a blue-suit environment but dress code has been more relaxed for some time; business casual for the most part.
Interview questions [1]
Question 1
Who knows? Again, there are 1000's of hiring managers with Aetna. You needn't worry what kind of tree you would be, if you were to be a tree. You may be asked why you want the position, what makes you the best person, etc. etc. Public sector work is a growing domaing at Aetna, so knowing about medicare, medicaid might be good, depending on the position you are seeking. I asked interviewees to complete a simple spreadsheet regarding weighted averages, when I was a hiring manager, but very few managers do anything like that.