Airlines are struggling against rising costs and competition

The world's fourth-largest airline said it had agreed to cuts of $215m (�123.3m) a year with the Air Lines Pilots Union.

The Professional Flight Attendants Association agreed cuts of $117m.

Northwest, which filed for Chapter 11 bankruptcy protection in September, has said it must reduce its staff costs to achieve annual savings of $2.5bn.

Chapter 11 bankruptcy allows a company to continue trading while it gets its financial affairs in order.

Cost cuts

The Minnesota-based airline has said it needs to renegotiate wage and benefit deals with its staff to save $1.4bn a year in labour costs.

In order to reach that target the firm still has to agree a deal with the International Association of Machinists and Aerospace Workers' Union.

As the two sides have failed to reach a deal, Northwest has filed a motion with a bankruptcy court in New York seeking temporary wage and benefit reductions of $114m.

Northwest is one of America's long established "legacy" airlines - but it has hit turbulent times in the face of increased competition from low-cost, no-frills rivals.

This additional competition, along with higher fuel costs and reduced passenger numbers after the 11 September attacks, has caused difficulties for airlines that have not been able to reform quickly enough.

News of Northwest's labour cost deals came as fellow airline Independence Air and its parent company FLYi became the latest US airlines to file for bankruptcy protection.