Tell me please which one of the following sentences sounds the most natural and correct?
I am flying to Canada first class.
I am flying to Canada in first class.
I am flying to Canada on first class.
I think that first one is the most and natural, but I have heard people say on first class. By the way, what if I use the word economy, do I say
I am flying to Canada economy
I am flying to Canada in economy
or
I am flying to Canada on economy?