Go into Edit Mode. (Tab KEY)
Select the top 2 vertices. (B KEY)
Extrude forward. (E KEY)
Select the side vertices and extrude sideways.
Extrude sideways two more times.
Do the same with the other side.
Extrude out in the back for wings in the back.
Rotate your view and select the vertices in the back.
Go to Side View. (>View >Side)
Extrude up.
Click Add Modifiers.
Click Subsurf. 
Work on the airplane to make it better.
Here is what I have so far.
