Delta has faced strong competition from rival carriers

The deal would see pilots accept a 32% pay cut in return for the right to buy 30 million Delta shares, unions said.

Delta chief executive Gerald Grinstein said the pact was a crucial step in securing Delta's future but warned that bankruptcy was still possible.

The airline has seen losses quadruple to $646m in the last three months.

The news of the deal sent lifted Delta's shares up 13% in morning trade in the US.

Tentative agreement

The Air Line Pilots Association, which represents Delta pilots, said a "tentative" agreement had been struck after on-off talks which have lasted more than a year.

This definitely helps them avoid bankruptcy in the foreseeable future Ray Neidl, Calyon Securities

It said the deal would have to be ratified by its members.

Mr Grinstein said the agreement was one piece "of a complex puzzle that must come together in time to begin to reverse the impact of high costs, including unrelenting high fuel prices".

Analysts have warned recently that Delta may have to seek Chapter 11 bankruptcy prevention.

Delta, which has been hit by the twin pressures of rocketing fuel costs and fierce competition, has said that it needs to cut between 6,000 and 7,000 jobs and reduce costs by $5bn (�2.7bn) a year.

"This definitely helps them avoid bankruptcy in the foreseeable future," Ray Neidl, an analyst with Calyon Securities, told Reuters.

"This is the lynchpin that will help the airline put together a package for restructuring."

In addition to seeking agreement with its pilots, Delta has made moves to refinance its debts.

On Monday, it announced a deal with bondholders to defer approximately $135m in debt due next year until 2007.

The airline also said it had agreed the terms of a $600m loan from American Express.