Yes there have been a handfull of American pilots with Ryanair. Some may have had ancestral rights but others had work permits obtained by a lawyer specialising in immigration issues and flew on validations. Pretty much all these guys were here on a temporary basis, at least in their own minds, and then were hoping to return from furlow to their old companies. I think the US pilot thing amongst Ryanair managers was a fruitless exercise and probably wont be repeated.