Northwest Airlines and Delta Air Lines are expected to announce layoffs in the next few days, adding their names to a growing list of aviation companies fighting for survival in the aftermath of last week's terrorist attacks.

Northwest, the fourth-largest U.S. carrier, is expected to announce an unspecified number of layoffs and a permanent 20 percent flight-schedule reduction on Friday, according to a source familiar with the matter.

The president of Delta Air Lines, the No. 3 U.S. commercial carrier, said Thursday in a recorded telephone message to employees that the company was faced with "absolutely no alternative" to cutting jobs because of the drop in demand for air travel.

The cuts will be announced next week, Frederick W. Reid, Delta's president and chief operating officer, said.

Airline job cuts also spread to Europe, with Europe's largest airline, British Airways,  announcing sharp cutbacks in jobs and flights.

No. 1 U.S. carrier American Airlines, No. 2 United Airlines and aeronautics giant Boeing Co. have already announced layoffs of up to 75,000. 

The attacks in New York and Washington have led to sharply reduced demand for air travel and a need for costly increased security measures. All major carriers have been running a 20 percent reduced flight schedule since the attacks.

Northwest was expected to meet with its unions Thursday, union officials said. There is no indication yet on the total number of Northwest's planned layoffs, although company officials declined to comment on a report in the Detroit Free Press that said it was planning to lay off about 10,000 workers. On Thursday, the company declined to discuss a Minneapolis Star Tribune report that said 22 percent of the company's 23,000 state employees were slated to be cut. 

Delta has about 80,000 employees, most based at the company's hubs in Atlanta, Cincinnati, Dallas-Fort Worth, and Salt Lake City. Delta is the largest employer in metro Atlanta.

American put an end to days of rumors on Wednesday by announcing that it would lay off at least 20,000 employees. American said the cuts will be spread across American, Trans World Airlines and the American Eagle commuter line. The companies have 138,350 employees.

United also came out on Wednesday with plans to cut about 20,000 jobs in the wake of the attacks. The cuts amount to about 20 percent of its work force of 100,000 people.

United has been harder hit by the disaster than other carriers. Not only were two of its flights involved, it relies more than others on revenue from business travel, which is expected to decline drastically.

Late Tuesday, Boeing announced it was laying off up to 30,000 employees by the end of next year. 

Industry experts said they expect about 100,000 airline workers to lose their jobs.

Federal Aid Package

The commercial aviation industry is making a hard — and desperate — push for a federal aid package, saying its very survival is at stake.

The White House has not yet requested the loan support the airlines are seeking, but U.S. House of Representatives Majority Leader Dick Armey expects Congress to approve a package that also includes up to $15 billion in loan guarantees.

The Bush administration is in favor of quick action to prop up the industry, while making clear that the aid should be directly related to losses from the attacks and should not subsidize past bad business practices by the industry. 

U.S. Treasury Secretary Paul O'Neill said that, if aid is given to airlines, it should be direct. 

"I favor that if we are going to give people money, we ought to give them money,'' O'Neill told the Senate Banking Committee. 

The Air Transport Association, an industry group, said the industry urgently needs all three components of the package Congress is considering — the direct aid, the loan guarantees and a limitation on liability for the damage caused by the attacks. 

"These three components are essential, as is the necessity for all three to be enacted promptly and concurrently in order to ensure our continued viability," the group said in a letter sent to President Bush. 

Besides downgrading the airlines' credit ratings, Standard & Poor's on Thursday placed all its North American airport ratings on credit watch "with negative implications," citing "a potentially severe and prolonged decline in activity that may be without precedent in U.S. history."

S&P also said the U.S. airline industry will likely need the federal government to impose relief from possible mountains of lawsuits seeking damages for the attacks.

Reuters and the Associated Press contributed to this report.