Flex Comp Questions

I understand that I can use flex comp for co-pays, prescriptions, etc.  However, I was wondering how they reimburse you for travel.  I am going to another state for my surgery.  I see that travel or mileage to/from doctor of hospital is covered.  Not sure if I'm driving or flying just yet.  Does any one know what would be covered?  I figured I'd ask here before I give them a call.  Thanks all in advance for your replies!