Painting small parts

Both.

If it's a small part that has a locating pin - eg landing gear, joystick etc, i'll cut off the sprue, glue the locating pin to a toothpick and then paint.

I do this because often these parts are attached to the sprue tree in at least two places - which means touch up would be necessary.

However, if there is no real way of doing this, i'll paint on the sprue then touch up afterwards. 

Also, i normally brush paint all small parts now.  I used to try and get all the ones of the same colour together and airbrush them, but now i find it much quicker to brush paint.

This is one of those "it depends" questions.  Sometimes I'll paint on the tree, but most times with small parts, I usually do some assembly 1st.  Maybe on the engine, or in the cockpit, it's just easier to do the assembly and then paint.  Usually airbrush the main color, and then do touch up with the brush.

Reid

I usually paint them on the tree.  Then, when I cut them from the sprue and clean up that spot, I must touch up that spot with a small brush or toothpick.

I always remove the parts, clean them  up with an X-acto and sandpaper and then hold them with small alligator clamps or stick them to a piece of cardboard with doubled over pieces of tape and airbrush them.

GreenThumb

I always remove the parts, clean them  up with an X-acto and sandpaper and then hold them with small alligator clamps or stick them to a piece of cardboard with doubled over pieces of tape and airbrush them.

I do the same thing pretty much.  I find it easier to paint after the parts have been cleaned up myself.