People are laid off all the time when sales are down, the market is bad, etc: there is no legal "right to a job" except whatever is in your employment contract. There is a legal concept of promissory estoppel which boils down to promises being binding. However, there has to be a clear and definite promise, not for example a statement like "we hope to bring you back after this is over".
Normally, the employer can argue that they have the right to fire you regardless of performance, and that would be the end of it. Let's say you have it in writing, and it is clear that they unconditionally promise to hire you back: you would want to (e)stop them from arguing that they have the right to fire you. The underlying idea of promissory estoppel is that such a promise keeps them from making that argument. But: it is not enough that they made the promise, you also had to rely on the promise and act / forbear from acting in some way because of that promise. It could be, for example, taking another job, or moving to another country, or simply looking for another job. The hard part, then, would be getting a clear and definite promise.