In a parallel thread, mike_hearn links to https://goatpath.wordpress.com/2011/02/11/how-much-can-an-ev... .

The 45 minute flight from Port Au Prince, Haiti (after the earthquake) to Santo Domingo, DR cost $841.11.

I think this is because 'full coach commercial fare' is the most expensive coach option. Very few ever purchase it, excepting those who want full flexibility to change the schedule without extra fees, or request a class upgrade if available.