@KillaKam04 easy! Get a cockpit you like, Click the Gear Button and you will see a button. tap it. then you can delete the previous one! Tha bad thing is you cant get the angled cockpit and the other turning cockpit as main.

I've just come out with a new plane I think I've gotten better at this

Thanks guys

@Gestour , well, you're absolutely right. I must have been mixing up the procedure for building successor airplanes.

You don't have to do all of that!
Just put the new cockpit on, and select set as main from the part options.
@ChiChiWerx @KillaKam04

First, you have to remove the cockpit off your plane. If the cockpit is buried (or "clipped"), you'll need to grab the part the cockpit is attached to. The rest of the plane will then "gray out". Drag the grayed-out plane to the upper left corner and make it a sub-assembly. Then, create a new plane with whichever cockpit you want. You will have to replace the default canopy by dragging in a new canopy, opening up the utilities menu and selecting "Set as Main". You can take the default canopy and delete it. Then, take the newly created sub-assembly from under your subassemblies menu, drag it onto the building pad, add your new canopy and voila, you've replaced your canopy!