I have had the luxury of both modes of travel between my European destinations. It's very important to look at the pros and cons of each method of travel.
Airplanes are all about speed, so if you have a limited amount of time this is the most efficient method. The Con to this is that it will be more expensive, and usually isn't worth it if your destination by rail is less than 4 hours away. Also, many people are more timid when it comes to flying...so fear can definitely sway a person's choice for travel.
The positive's of travel by train is that they are less expensive, can be extremely efficient, and you have an ability to view the countryside. High speed rail is obviously the way to go, with speeds up to 210 kph, I remember the train from
The Cons- Longer train rides can be extremely tedious. I have done multiple overnight trains (Paris-Frankfurt, Paris-Madrid), and let me say...sleeping on them is not easy, typically being loud, hot, and uncomfortable depending on the train.
What do you think? Do you have any personal experience to share?