Northwest Airlines Corp. (NWAC) raised fares aimed at business travelers by $50 each way on Friday, which, if it sticks, would be the largest of several price hikes by the nation's older airlines this year.

The move pushes back against fare caps Delta Air Lines (DAL) adopted earlier this year.

In January, Delta capped one-way coach fares at $499, and most other airlines followed, at least on routes where they compete with Delta. Northwest's action on Friday is the first to push through that limit.

A Delta spokesman did not immediately return a phone message left by The Associated Press.

Northwest and several of the other older carriers have had several small fare increases this year. But Northwest has benefited little from those increases because discount carriers haven't matched them, said Tim Griffin, executive vice president for marketing and distribution, in a message to employees released by the company on Friday.

"The prior increases have run their course and we need to be more targeted in our approach," he said.

Eagan-based Northwest also added a two-night minimum stay requirement to some fares that used to require just one night's stay.

Northwest shares rose 11 cents, or 1.8 percent, to $6.35 on the Nasdaq Stock Market (search). Delta shares dropped 6 cents, or 1.6 percent, to $3.79 on the New York Stock Exchange (search).