Think about your parents letting you take the high-speed train. You may think that the high-speed train is safer than the plane at first, and you are worried about your own safety. I hope you can come back to him safely. This is the first point.
The second point may be that the price of high-speed rail is still a little less than that of aircraft. I hope you can save some money. After all, you are a college student, and you are still a consumer group. You haven't made ends meet, or you have more than one income.
Most importantly, you still need to have better communication with your parents. I think the communication between you is still not perfect. Although you said the plane ticket was cheap, your parents didn't know about it. The safety of the plane also needs you to teach your parents science. You can have a good chat, and naturally there will be nothing.
After all, everything depends on communication. After communication, these problems you mentioned no longer exist. What parents don't want their children to live comfortably or come back better, but sometimes some parents' ideas may not be on a parallel line with yours, so you need to communicate. Tell them what you think and make them accept it. As a new human being in the new era, you can also understand their difficulties as parents.