tool to keep chain in place when wheel is off
 

I recall reading somewhere that there was a tool that can hold the chain in place when the wheel was removed . this would be useful when I take my folding bike in the suitcase when flying. Does this tool exists or am I just dreaming?

Pedro's makes a gadget to hang you chain on when the wheel is removed.
http://pedros.com/chainkeeper.htm
it's called a chain keeper.

yes, I think that is what I saw. Does this tool also make it easier to put the chain back on the wheel when the wheel is reinstalled?

The Pedro's is primarily to hang the chain on when the wheel is out. Back in the 80's there was a tool called a Toureze chain keeper. It held the chain up when the wheel was out, and held the chain when you installed the wheel. They haven't been available for a long time.

http://i185.photobucket.com/albums/x...h_PICT0042.jpg http://i185.photobucket.com/albums/x...h_PICT0043.jpg