Rep John Mica, a Florida Republican and former chairman of the House of Representatives aviation subcommittee, told a hearing on the merger proposal the deal to create the world's biggest airline did not appear anti-competitive.

Democratic colleagues on the panel predicted the merger would probably lead to service and job cuts and usher in other mergers to further narrow choices for consumers.

'In short, the pending merger places at risk the consumer benefits of airline deregulation,' said Mr James Oberstar, a Minnesota Democrat and chairman of the House Transportation Committee.

But Mr Mica said it was more likely than not that 'this merger will be granted' by officials at the Justice and Transportation departments who are reviewing the potential impact on competition and service.

Antitrust and industry experts have said previously the Delta/Northwest proposal stood a good chance of winning regulatory approval.

A senior official from the Justice Department's antitrust division, Mr James O'Connell, told the hearing that he could not comment on the case.

But Mr O'Connell said competition in the airline industry 'is critical' and said the agency has a 'strong record' of 'enforcing antitrust laws' in the industry.

'We will look at all aspects of competition to determine what the current state of play is and determine whether the transaction would change that state of play,' he said.

Delta proposed in April to acquire rival Northwest in an all-stock deal. Executives of the merged company say they plan to expand service, especially overseas.

So far, the proposal has met little or no resistance in Congress, which cannot block a deal. Lawmakers, however, can disrupt the timing of the regulatory review, influence policymakers and rally consumers and workers.

Aviation subcommittee Democrats gave the chief executives of both airlines - Richard Anderson of Delta and Douglas Steenland of Northwest - their toughest public review yet.

'Previous airline mergers have rarely produced the projected benefits and efficiencies promised,' said Rep Jerry Costello of Illinois, the current aviation subcommittee chairman.

'This has frequently led to reduced competition and higher fares.' Delta estimates annual cost savings and revenue gains of at least US$1 billion (S$1.38 billion) for the merged company. Of roughly US$700 million in projected cost savings outlined by Anderson, at least US$150 million would come from combining airport operations. Another US$150 million would come from paring corporate overhead.

Delta estimates roughly 1,000 job losses from the deal. -- REUTERS