If you can leave at 10:45, 11:45, 12:30, 13:30, 14:30, 15:30, 16:00 etc. it's a ± 4 hours ride. No flight can compete.
I come up empty for Fllorence, Bologna and Pisa. A train at 9am takes 4:52, change in Bologna. If someone comes up with a flight, IMO you are better off on the train.
Train is much more convenient, as you have to allow five hours if flying
By the way I understand that you are looking for a faster solution, but please note that you have also different couch lines, here's a few links
It is basically no traveller-friendly journey: the distance is too short to make flights convenient; after all, it is not really short too and there are important mountains to cross. Certainly, considering train or bus sounds much more sense than going to Bergamo just to fly down.