CHICAGO, Jan 15 (Reuters) - Credit Suisse First Boston analyst James Higgins said on Tuesday he upgraded UAL (UAL) Corp., the No. 2 U.S. airline, to "buy" from "hold" as it participates in an early sector-wide recovery. Higgins said in a research note that he believes UAL management will convince labor that wage givebacks are necessary to stabilize the company financially. His new target price is $23, about 62 percent above current levels. Higgins also issued a report about the airline sector overall, saying he sees "glimmers of hope" about a 2002 recovery, based on recent visits with senior management at AMR Corp. (AMR), Continental Airlines (CAL), UAL and Northwest Airlines (NWAC). In addition to the UAL upgrade, he is reiterating "buy" recommendations on AMR, Northwest, Continental and Delta Air Lines (DAL).