How create such an complex shape? (Form Tool?)

[yak52russ]

Hello,

I have a problem and would like to get some advices how I could create such a complex shape.

At the moment I am building an Airbus airplane model and there is a peace between the wings and the fuselage witch goes under the fuselage and goes over the wings. To understand what I mean, I added a picture where I color this component in magenta.

Here are some other pictures to understand what I mean:
https://upload.wikimedia.org/wikipedia/commons/7/7a/D-AINM_Lufthansa_A320neo_FRA_%22Freising%22_%284...

https://freeware.aerosoft.com/forum/screenshots/monthly_11_2017/-2016-dec-23-006.jpg.d85f6cea094b44f...

My question is, how could I create this complex component? Do I have to use the “Form” tool or is there an much easy way to create it? I am not very familiar with the form function and it seems very difficult to me. If I am forced to do it with the Form tool, are there some good free tutorials where I get a good explanation of the “modify” applications?  
I build the hole model with the function "solid", can I change later the Form body into a solid body?

[blaster701]

You could use the form tool, but I would say that you might have better luck with using traditional Surface modeling.  A series of lofts or patches supported by guide curves would be a good way.  You might not be able to do it in one step.