Hi, I'm a middle school student living in Korea. And I have a question about English grammar.

The question is, is this sentence "My hobby is to make model planes" grammatically right?

That sentence is written in one of the most famous English grammar book in Korea. And my school teacher taught me that. But, few hours ago, my new school teacher told me that, that sentence is wrong. She said I should use -ing like "My hobby is making model planes"  instead of to + infinitive, because -ing and to + infinitive have different meanings. But, the grammar book, and my ex-English teacher told me that -ing and to + infinitive are same meaning and can be changed each other.

I'm really confused by this question. Would you please tell me what is wrong and what is right? I would be pleased if I got the answer. Anyway, thank you for reading this post.

Choi, Ji-sung
They are both correct.

The first version is not normally used though. It sounds very stilted.
Thank you:)