Cockpit
As the main mission of the Harrier has usually been support of troops in combat, rather than long-range interdiction, it has always been acceptable to have only one crewmember. This has allowed weight to be limited, reduced the problem of maintaining the aircraft's centre of gravity and allowed a larger proportion of internal volume to be used for fuel and equipment. These points have been illustrated by the problems found in all these areas with the development of two-seat trainer Harriers; all of with have featured operational penalties. In the first generation of Harriers the lack of importance attached to rearward vision that resulted from the ground attack mission also enabled the drag to be minimised by adopting a canopy flush with the upper-fuselage lines. This has been reversed in the case of the Sea Harrier and Harrier II, which both feature a bubble canopy to both improve rearward vision and as a consequence of increasing cockpit volume. However, these gains have come at the cost of greater weight and drag in both cases.