An air-thrust marine vehicle has a hull with upwardly extending hull sides. An air-thrusting propulsion unit is configured for detachable mounting on the gunwales of various width hulls. The propulsion unit has a base assembly configured to move between a retracted position and plurality of expanded width positions for accommodating various width hulls, while being configured to hingedly engage the gunwales. The propulsion unit can be removed from the vehicle and positioned on another vehicle, such as a boat, an ice- or snow-traversing vehicle.