How do I get an object to stretch between two animated objects? I want to animate this LEGO x-wing closing its wings, and have managed to rig up bones to control the wings so they close on the correct rotation, but it has this elastic band on the back that needs to be on those two black pieces and stretch between them when the wings open and close. How to I do that? 

I'm thinking weight painting is involved? Do I make a bone on each black piece?

I'm only new to blender only this year so please explain as basic level as possible please! Many thanks in advance!
I can suggest two options:


if you want to use it in 3d engines (with only bones animation), you can use two bone system:


One bone at one black thing and weight paint it (gradient) to the parallel part of the rubber mesh.
Second bone at the other black part
attach "track to" modifier to the first bone with target as second bone.

Make a "Shape Key" of the rubber with stretched pose, and move and rotate as required. You can also use both (1 &amp; 2) for easy animation and right mesh deformation.