US Airways Group shares on Wednesday built on the prior session’s gains to buck a retreat in the broader market and lead a relatively strong move higher by the airline sector.  The stock was given a lift by a J.P. Morgan Chase upgrade on Tuesday and was the beneficiary of more rosy analyst commentary Wednesday. “The recent decline in oil would add as much as $3.00 per share in annual  earnings, and although we are not adjusting our estimate at this time, we believe the consensus estimate will have to move higher, especially if oil prices remain at or around current levels.”