Could you clarify your assertion that it would be massively more expensive? A quick look at the numbers suggests that a 737 MAX 8 is about 10% more efficient o

Could you clarify your assertion that it would be massively more expensive? A quick look at the numbers suggests that a 737 MAX 8 is about 10% more efficient on fuel burn compared to a 737 300. That is not "massive" in my book and I'm more than happy to pay a little bit more per ticket if it means a higher safety margin. Did you mean something older and less efficient than a 737 300?