I fully agree with you. I'd fly too. The scenery from the train worths it only between Aix/Marseille and Nice. And the travel time is no brainer. And what I read here in this thread is the usual mistake : people compare the train trip duration (5.5 hrs here) to the total travel time by plane (flight duration + travel time to/from airport + waiting time at departing airport). But with the train, you also need to arrive at the station, wait a bit (unless you always want to board your train 1min before departure) and travel from the arrival station to your final destination. Applied to the OP's case, it will result in a total travel time of approx 7hrs by train and 4h15 by plane. I'm not saying that the train is a bad option but we have to compare options correctly. And remember that NCE airport is downtown (so no benefit compared to the train station on the Nice side) and that landing in NCE is one of the nicest I know (seating on the left side).