Slow the plance down as much as you can, you don't get bonus points for doing it quicker! If your minimum speed is above 4 bars you will be able to slow the plane down to a minimum of 4 bars once you are over your ship. To land successfully you must have a shallow descent and have your landing gear down! If you overshoot or can't be bothered to land press escape when your over or past your landing area.
You get 50 points for a boat, 25 for a plane/tank and 10 points for a soldier. Soldiers can also die by getting hit from shrapnel from nearby explosions so keep an eye out for that!