(Adds details on possible Continental spinoff paragraph 5, adds Delta Air Lines comment paragraph 9, other details) CHICAGO, Feb 20 (Reuters) - Major U.S. airlines may look to shed wholly owned regional carriers this year as they seek ways to shore up balance sheets hurt by the travel downturn following the Sept. 11 attacks, an analyst said on Wednesday. The current focus on additional liquidity may be a catalyst for many major U.S. airlines to spin off wholly owned regional carriers, Susan Donofrio, senior U.S. airline analyst at Deutsche Banc Alex. Brown, wrote in a research report. Continental Airlines (CAL), the No. 5 U.S. carrier, AMR Corp. (AMR) and Delta Air Lines (DAL) are the most likely candidates to spin off regional carriers in the near term, in that order, Donofrio wrote. "We would expect Continental to potentially be the first one out of the gate after its planned Continental Express (IPO) was, understandably, taken off the table in September," Donofrio wrote. Continental said in its fourth-quarter financial report in January that it intends to pursue a Continental Express spinoff, though the structure and terms of the offering will be revised and the timing remains uncertain. After No. 1 U.S. carrier AMR Corp. completes contract negotiations with American Airlines pilots, American Eagle might be next on the block, Donofrio wrote. A spokesman for American Eagle declined to comment on the analyst research report. Delta, the No. 3 U.S. carrier, may be rethinking owning some regional carriers given past labor issues at its wholly owned unit, Comair, Donofrio wrote. Delta also owns Atlantic Southeast Airlines. Delta is pleased with the performance of Comair and Atlantic Southeast and has no intention of spinning off those regional carriers into separate companies, Delta spokeswoman Catherine Stengel said. Northwest Airlines (NWAC), the No. 4 U.S. carrier, and Alaska Air Group (ALK), ranked No. 9, are likely to wait before spinning off wholly owned regional carriers, she wrote. Northwest and Alaska Air have just started to convert fleets in Express Airlines I and Horizon Air to regional jets respectively, a process that has driven high valuations for publicly traded Atlantic Coast Airlines (ACAI) and SkyWest Airlines Inc. (SKYW), she wrote. Using publicly traded regional airlines as a measuring stick, most of the wholly owned regional airlines are worth at least half of the value of the major airlines, suggesting potentially sizable shareholder value, Donofrio wrote.