I have a link to a fully built digital version of my airplane on Lego Digital Designer, but you will only be able to access it if you download the program (it's free). You should be able to build it fine by following the step-by-step build plan that the program has except for three more complicated steps that the program was not able to do. Those are the only steps that I will include in this project.
Step 1: Attach the Tail Fin
The tail fin in the program has two bright yellow pieces that are meant to show where and how it fits in. You do not actually need to include the 1x2 wall element (bright yellow) in the back of the fuselage; it is just there to represent the 1x2 piece (also bright yellow) on the tail fin. The second picture in this step is an example of how the fin attaches with the extruding 1x2.
Step 2: Attach the Front of the Underbelly
Sadly Lego doesn't have a piece like the one in the second picture but I used a Mega Blok to attach the bottom of the propeller mount. Hot glue would be a good alternative to the double-sided piece and I have found that it is very useful with Legos because it holds well but is easy to get off if you want to take it apart.
Step 3: Angle the Back of the Fuselage
The digital designer would not allow me to angle the back of the fuselage as much as I did for the original airplane. You should be able to tilt it enough that it snaps in at the bottom.