US Airways was quick to point out that the slots that Delta is getting are currently being used by the US Airways Express operation, and that mainline US Airways service (including the Shuttle) won't be touched. Still, it's possible that mainline traffic could take a hit if there's less traffic being fed into LGA by the Express carriers, which will stop flying to 26 destinations from LaGuardia. And there will be around 300 layoffs at the airline's Piedmont regional subsidiary.
But the airline also gets some interesting assets in return.
Let's look at Delta, which already has significant domestic and international operations across town at JFK. The airline's press release notes that the airline will "build a hub operation at LaGuardia that will increase the number of customers served... without increasing congestion." It'll do the same thing that US Airways plans to do at Washington - operate larger planes. "
The airline also plans to spend $40 million on a project to upgrade and rebrand the US Airways and Delta operations at LaGuardia, so it's clear that they're planning on making this a hub. At the same time, "Delta will continue to invest at its hub at New York's leading international airport, John F. Kennedy International," the airline said. So now the airline will be pursuing a rather interesting strategy of operation two hubs in the same city, one of which is primarily international and the other domestic. This could pose some interesting challenges; what happens to passengers seeking to connect between the two airports for an international or a domestic flight?
For more information, check out the US Airways press release here and the Delta release here.