Been messing around with Google Sketchup. I'm pretty much done with the design, but when I try to move the pieces around they all seem to be connected, and change shape. Some have been made into components and some have not, but it doesn't seem to matter, it always happens. What am I missing?

Sounds like the problem I have been having. I found that by ensuring that I created each section of the build as a component before drawing the next bit I have managed to avoid this in my latest attempt. I also try and draw new sections into a new layer so I can remove bits of the airframe as and when I need to for fine tuning.

Make each part a component or group before you draw the next part.. you can also introduce layers for different groups, this gives an easy way of showing the build steps, turning one layer on at a time.
By making groups or components you can lock them up nice and safe.
and...You can move them without affecting the other bits
oops! thats what the previous post said...sorry but thats the best method

more sketchup info here https://www.rcgroups.com/forums/showthread.php?t=920416
might be of use... dave

try copying each piece, then make them components. then put it back together. i have had to do this myself a couple of times.