@sflanker When I tested my plane it's all disconnected

basically like sp just more complex, what you need to do to mess with fuselages is a little thing in the top of the bar on the left side of your screen, click that and go to the bottom on the drop down section, make sure your on a fuselage piece, and you should be able to edit it just like in sp except the increments and the max allowable values are going to be way larger, you can also more precisely customize the corners. that should help a bit. i can elaborate a bit more, but don't expect me to respond to quickly, i rarely check sr2.

Do you have any specific questions? Here are some basics:

• Wings generate lift (duh, right?)
• Your center of mass needs to be forward of your center of lift to make your craft have stable pitch.
• The angle that your wings are at when sitting on the runway needs to be slightly upward, so adjust your landing gear accordingly (otherwise you'll generate downforce).
• Jet engines need tanks with jet fuel (duh, right?)
• The front end of a jet engine needs clear line of sight forward, or you need an inlet with a clear line of sign forward.
• Wings and fins will need control surfaces to give you pitch, yaw, and roll
• Mirroring is your friend, but sometimes you need to tweak control surface settings.
• Wings need to be exposed, not covered with other parts, although there are part settings that make it possible to have effective wings covered by other parts (which people do to make the wings look less blocky.

This plane that I made has links to a series of unlisted crafts that were the steps throughout the build. However note I'm no expert, and this plane was created before cockpits and transparent parts were things.