ORIGINAL: FERNDALE AIR FORCE
My thought is that the changed the formulation of the styro.
Could be. There's many types of foam.
Beaded foam, most commonly used and cheapest and break appart cleanly.
EPP foam, very durable and easy to repair.
Flex-Foam, probably what the AA has and holds it's shape well.
And Depron, which is very strong and light and used for small planes
but usually needs some type of bracing.