With regards redundancy, you cannot make a position redundant only to employ again in the exact same job role, the role has to have been diminished and a new different role created. For example, if you have a business with a van driver/logistics only position, you can make that position redundant but you could re-employ them (on different terms as they can re-apply) or someone else with a different role, such as warehouse and logistics.
So how you can make a Captain redundant and re-employ them on reduced terms I'm not sure as you can't them make them Captain and cabin crew, the position wouldn't allow it.