Not sure having certifications makes a business ethical (whatever that means in the world of commerce). I would suggest the standard all airlines should seek to attain is set by Southwest. I haven't ever felt they have 'screwed' me, if only they would interline. I don't know any who come close to that standard.
Of cours I have only flown a small percentage of the world's airlines, but the European ones who claim to be modelled on Southwest are some of the worst.