when redundancies were suggested (but ultimately not needed in the end) in my company, quite honorably most people put forward ideas of part time, job share etc rather than put someone on the street in the current climate. (so we're not all like the MP's after all!)
The company said that part time and job share didn't save as much as one would think, although you save a salary, you still have all the recurrent training, sim traing, lcencing costs, medical costs, recency and currecy requirements to worry about.
I'm not sure of the economics, but ultimately its not going to save the company as much as one thinks it might. So don't be surprised if they don't welcome your suggestion with open arms