Delta Air Lines has put on hold plans to sell its Comair regional jet service division while it explores a possible merger with United Airlines or another rival, the latest sign that 2008 could be the year US carriers press for consolidation.

Delta executives said in October they would reach a decision on whether to sell or spin-off Comair within the next several months. The Atlanta-based airline has had preliminary discussions with JPMorgan Chase on its options for the unit. It will not retain the firm until a special committee of Delta directors and their bankers – Merrill Lynch and Greenhill – has completed the merger review, people familiar with the company’s plans said.