It seems like a furlough resulting from a lower seniority number would be a lot easier to take if you had the full retirement check coming in each month. If you leave early you have to consider the possibility of a sickness or injury that could result in you losing your medical. Then there is the possibility of your airline merging and the two pilot groups having to merge their seniority lists. You are leaving pretty much a sure thing to work for a company that, in all likelihood, filed for bankruptcy just to avoid promised pensions and benefits for an earlier group of employees.