You have to build the plane out of a lot of brushes. You're going to need to use the slice tool and/or the vertex tool to make all the different angles.

Start by building the basic stuff like the inside walls/floor/ceiling that the players touch. The fill in around that to make it look like a plane.

Make a trigger_hurt to kill players down by the ground.

Make a func_door for your sliding door and give it a name. Make a func_button and have it target your door by name.

You'll probably need at least ten to make it even recognizable as a plane.

I would probably use over 100 brushes to make a plane but that's because I'd have a lot of detail and I like planes... PLANES!!

You want to make the plane drivable?? Well you have to make it a func_vehicle then and I can't help you with that. Google for func_vehicle if you must do that.

You don't need to use the slice tool. Try just the vertex manip tool (Shift+V).

The slice tool is the button with part of the block missing. Select a brush, click the slice tool. Then click 2 points on one of the 2D views to make a line. The line will slice the brush when you hit ENTER. You can move the line's endpoints around first if you want to.