I'm being a bit cheeky here - this comes in under the 250 parts limit but is both a boat and a plane.

Group 1 activates the main engines. These can be used to fly the plane as normal and have enough power to get it over 750 mph.

Group 2 activates the VTOL engines. These can be used for vertical take off and are the recommended engines when using this as a boat.

Group 3 activates the steering nozzle, which runs off the VTOL engines, so you'll need group 2 activated as well. This allows you to steer with the yaw control while using this as a boat.

Group 4 drops the cargo container.

Judging criteria results: Take off speed can be zero with the VTOL engines. Top speed is over 1100 mph in plane mode when the cargo pod has been dropped and the VTOL engines are being used for extra boost. Boat top speed is about 170 mph using VTOL engines, this can be increased by activating the main engines but this tends to result in loss of control. Fuel left after flight from Wright to Yeager is over 60%. Cargo is 12000 lbs, this is already loaded in the central red pod.

Features and abilities are that this can act as a plane, a boat or a seaplane. The central cargo pod can be detached on the runway and has two methods of separation. The hard way is to use the VTOL for a vertical take off, leaving the pod behind. The easy way is to get a little speed, use the VTOL to pull a wheely, then use VTOL to thrust backwards, allowing the container to roll out from underneath the plane.