Turn left on entering the plane and there’s a dilemma swirling around the expensive seats: Do biz class passengers need privacy doors or are they a waste of space and weight?

The list begins with the E 450 All-Terrain, E 450, and E 53 versions of the 213-series Executive Class. The remainder comprises the CLS 450, CLS 53, GT 43, and the 53 series of the GT 4-Door Coupe.