This is from a Permanent Ryanair's Contract of Employment issued in Oct 06
20. Excess Capacity
20.1 Because of the uncertainty of the airline business circumstances could arise where Ryanair has excess capacity. If required to reduce our activity level for any reason, it is a condition of this job offer that you accept the right of the Company, at its sole discretion, to give you compulsory unpaid leave for the duration of the period of excess capacity or to terminate your employment.
A few points
Yes a company can put you on compulsary unpaid leave
Yes you can claim unemployment benefit
No you can't work anywhere else
But
The said company cannot use ( unless they are pilots on permanent contracts ) or employ someone else to do your job so if pilots on permanent contracts are on temporary lay off which is what it's called, no one (unless they are pilots on permanent contracts) can fly ryr planes
After 21 working days you can request redunancy the company must either reinstate you or make you redundant
If the company reinstates you, you can't be put back on compulsary unpaid leave for a period of 3 months
No company can just terminate your employment without good reason ( lack of work is not a good reason ) you have to be made redundant
And lastly if you sign a contract which is found to contradict the employment laws that part of the contract is void
I went through this 12 years ago with another company ( non aviation ) to the best of my memory these facts are correct