A watercraft with at least one onboard propulsion engine includes at least two hulls and a wing-like deck structure spanning the two hulls (a floating wing). Port and starboard skirts combine with the deck structure to form port and starboard planing channels. The deck structure includes an upwardly facing surface that slopes downwardly toward an aft end of the deck structure in order to provide aerodynamic lift. Preferably, a speed-responsive exhaust proportioning system vents exhaust at vertical steps in planing surfaces on the hulls to reduce drag, increase lift, and reduce thermal signature. One embodiment includes hinged laterally extending deck extensions that an operator can raise to reduce vessel breadth during docking, upwardly extending barriers on the deck extensions that reduce the escape of wind laterally, and hinged flap structures disposed rearwardly that enable an operator to adjust vessel trim.