We flew into Miami the day before the cruise, December 21. Flying in the morning of the cruise is risky, and I proved that by missing my flight and almost missing the cruise a few years ago.
I originally started looking for flights in July, right after we booked the cruise. Initially, there were only nonstop flights on American Airlines, but ideally I wanted to fly Delta because I was pursuing Silver Medallion (also every time I fly AA, I say that I will never fly AA again). I set up Google Flight Tracker to track flights from LAX to MIA. A few weeks later, a new nonstop Delta flight from LAX to MIA appeared, and it was very affordable. I booked Comfort+ seats.... then the next day, I was playing around with the Delta change flight feature and realized that I could rebook First Class for only an additional $125 per person. I decided that this would be a nice surprise for Aaron and a fun way to kick off our vacation.
About a month before our flight, I got an email from Delta saying that our original flight was canceled, but they rebooked us on another flight. Unfortunately, we were no longer nonstop and would be connecting in ATL. Also, while our arrival time remained the same, our departure time now moved from 10AM to 7AM. The good news is that we were booked in First Class on both flights. I was worried that Aaron was going to catch onto my surprise when they emailed him about the rebooked flight, but luckily it went unnoticed. I also thought that he may notice the day before our flight when he checked in on the app, but again, he didn't.
It wasn't until we were at the airport. I took us into the Sky Priority lane to check our bag, and I was sure by then that he had caught on. "Merry Christmas!" "Is this for your status stuff?" "No, I upgraded us to First Class!" Had I known that the Sky Priority line hadn't given me away, I think we could have made it to the gate, and he wouldn't have noticed until waiting for them to call our Boarding Group. After the news sunk in, Aaron was very excited.... or as excited as one can be at 6AM - it was a good surprise.

In addition to our checked bag (Away Medium Checked), we each had the Away Bigger Carry-On. Aaron packed his suit and blazer in the Seyfocnia Garment Bag which rolls up into a duffle bag. We're skeptical that this actually qualifies as a personal item, but we didn't have any issues this trip... possibly because we were in first class, but also Aaron took the duffle off of his rolling bag and carried it on his back which made it look pretty unimposing (a hack that wouldn't work for someone my size). My personal item was my Brevite Camera Bag. I also used a magnetic hat clip to bring along my hats.