Today was my second attempt at making this recipe. I think my problem the first time was that I was too impatient in letting the layers cool, so blue and yellow made green. (I also discovered that Jell-O can in fact be too old. I had a box of cranberry that had become ickily sticky, so I ended up using sugar-free raspberry for the red instead.)
1 package (6 oz.) blue Jell-O
1 package (6 oz.) yellow Jell-O
1 package (6 oz.) red Jell-O
3 packets Knox gelatin
In a medium bowl, combine the blue Jell-O and one package of the Knox gelatin. Add two cups boiling water. Dissolve gelatin. Add 4-5 ice cubes, and stir until mixture is thick (or until the ice cubes dissolve). Pour into a 9×13 pan and let set completely. Repeat with yellow Jell-O and pour it over the set blue. Repeat with red Jell-O and pour it over the set yellow.
Needs More Butter 
Hey way cool. I don’t have ‘Jello’ in Australia where I am, so do yu think it would work with Aeroplane Jelly?
I had to look up Aeroplane Jelly, but it seems to be a gelatin product, so, yep, I bet it would work!
Okay cool, thanks a heap. It looks really cool, and I want to make it for my little sister’s birthday party.