can anybody tell me how to develop a new plane from scratch ? What are the basic steps and tools ?Thanks, Elvira.

It depends on how quickly you want to create this new aircraft.

1) Download and read/study the MSFS SDK's from the MS support website.2) Read the messages in this forum.3) Read the tutorial files available at http://freeflightdesign.com4) Decide which modeling program to use: GMax (free), FSDS2 (payware-reasonable cost), Max (commercial-horribly expensive!)5) Set aside at least six months of "freetime" in which to learn and practice! ;)

Just to add to Bills comments, study the aircraft source files that Microsoft supplies or any other model source files that you can find based on the software you decided on. Once you have the software of choice installed, practice exporting them till you get the hang off the steps you go thru to go from the drafting phase to a flyable model.Lou

it also depends on what kind of aircraft you are going to make.