[awesome_dude]

The analogy doesn't hold.

Airlines adjust capacity to demand — empty seats represent foregone revenue and future flights get cancelled or downsized.

Cargo ships don't work that way. A container ship returns to Asia whether it's carrying 1000 containers or 5000. The marginal emissions of an additional backload container are genuinely close to zero, not as a rhetorical trick but as a structural feature of how bulk shipping economics work.