I'm flying on the economy ticket.
With either BM or UA, at the very worst can I join them after my year away and get all the mileage from that year credited?
Finally, if I manage to join a FF before I leave, and I start racking up the points, would I actually get to silver status on BMI (16000 miles) say, and start being able to get into the lounges half way through my trip? Is that how it works?