Airlines swap assets in New York, Washington, D.C.

— -- The deal, which revolves around the trading of time-specific landing rights, called slots, at two of the nation's most congested and important airports —New York's LaGuardia and Washington's Reagan National — also is the biggest signal yet, experts say, that the U.S. airline industry is undergoing a major alteration in the way the carriers compete.

Other signals:

Delta, which became the world's biggest airline last year by acquiring Northwest, now aims to be the biggest carrier in the New York travel market, one of the world's largest and most lucrative.

It already calls John F. Kennedy International Airport an international hub and offers 200 flights a day there with service to about 50 foreign destinations. Now, it plans to turn LaGuardia, where US Airways' market-leading 23.3% share of capacity will be shrunk by the deal, into what it's calling a domestic hub.

When the changes are complete, nearly 30% of Delta's entire capacity, measured on a seat-mile basis, will flow through one of New York's three big airports.