President and CEO Doug Steenland blames the cuts on fuel costs that have more than doubled in the past year.
Northwest says it will offer voluntary departures. It says furloughs will be used only if it does not get enough volunteers to reach the 2,500 number.
Northwest also says it will begin charging $15 for the first checked bag, matching a fee added by other carriers this year. And the airline says it will begin charging a fee for frequent-flier award tickets -- from $25 for domestic tickets to $100 for flights to Asia.
A spokeswoman for Delta Air Lines Inc., which is buying Northwest, said record high fuel costs are causing the Atlanta-based carrier to look at everything. "However, we have made no changes to the service we offer to customers for a complimentary first checked bag," spokeswoman Betsy Talton said.
At American Airlines, the first major U.S. carrier to announce a fee on first checked bags, spokesman Tim Smith declined to comment directly on Northwest's moves, "but their actions clearly show they are facing the same extreme challenges all airlines are dealing with these days."
Executives of American parent AMR Corp. said last week they expect to cut 8 percent of the work force, or about 6,800 jobs.
Continental Airlines Inc., which has announced 3,000 job cuts but doesn't charge for checking a first bag, declined to comment on Northwest's actions.