Normal
That is a good question. I would say that no you couldn't book air through cruise line to arrive before the sail date. The cruise line probably only has staff at the airport on the days they sail. That is just my opinion. I could, and probably am, wrong. I just got back from going Northbound. I liked it because the scenery got better as you go. But I have also heard people say that if you are doing a precruise land tour with it it is better to go Southbound. But for cruise only I would definitely recommend Northbound.