It's not a like-for-like comparison:
- direct train vs. flights with layovers
- date and time of your choosing vs. a date and time not of your choosing, some time in the next month(?)
- buy in advance vs. buy on the day
- direct train vs. flights with layovers
- date and time of your choosing vs. a date and time not of your choosing, some time in the next month(?)
- buy in advance vs. buy on the day