Alcoa reports that it has developed new alloys that are as strong as composites but cost less. Composite materials are harder to work into the right shape (as they have to be made in layers in their final form, not produced in bulk for various later uses as metal is) and are hard to repair when damaged. This is an important consideration for modern combat aircraft, which contain a lot of composites and are harder to repair combat damage because of the composites.--Stephen V Cole