Think about it!
From a USAir shareholder's perspective, your stock has effectively doubled overnight from the proposed merger--as do most stocks that I have seen from companies being taken over.
And from the UAL's stock holders perspective...this will drive down the price of their stock short term, but as far as long term growth on the east coast--they have it made. Give it s couple of years or less, and the stock will take off IF and when the merger has been approved.
I guess if I were a day trader with a lot of USAir holdings, I would be looking to retire now.