) -- While




US Airways


have been working on a merger and


(UAL) - Get Report

has been working on fixing a broken merger,


(DAL) - Get Report

has been working on capturing the world's largest travel market.

That is going to make it tough for the new American to make up ground in New York, where Delta has been expanding aggressively at both Kennedy and LaGuardia airports and where United's Newark hub remains the country's most profitable airport operation in terms of profit margin.

Still, being the world's largest carrier means having a major presence in New York. "The battle for New York isn't over yet," said aviation consultant Bob Mann. "If American had emerged alone from bankruptcy, I think it would have been largely over, but the US Airways/American tie-up means there may be a second campaign."

So far, US Airways has said little about its plans for New York. Asked in a recent interview how US Airways' Philadelphia and American's Kennedy hubs would be integrated, President Scott Kirby said the two "are complementary today (because) Kennedy is mostly a local market, serving customers to and from New York," while Philadelphia is both a large local market and a major connecting hub with 437 daily departures to 113 destinations, 86 of which are domestic.

Knives and golf clubs on airplanes? Flight attendants don't like the idea >>

By contrast, American's JFK operation offers 92 daily departures to 48 destinations, just 29 of which are domestic. A high percentage of its passengers originate locally. Delta today is the largest carrier at JFK in terms of capacity, with about 40% of the available seat miles, while


(JBLU) - Get Report

is the biggest in terms of departures, with an average of 112 daily and peak daily departures of 159.

Before the merger, American was looking to JetBlue to help expand its JFK connectivity. At the JP Morgan investor conference on Monday, JetBlue CEO Dave Barger said, "We look forward to deepening and expanding the relationship with American Airlines and we'll see how that plays out." American had envisioned a code-share agreement, in which the carriers can write tickets on one another's flights, and had insisted on providing for such an agreement in its contract with the Allied Pilots Association.

But the reality is that US Airways probably has limited use for a code-share agreement with JetBlue, conceived during the period when American was resisting a merger, because US Airways would prefer to use Philadelphia. Airline geeks enjoy discussing all of the barriers involved in connecting passengers between airlines at JFK (I was involved in three such discussions on Tuesday), but given the ease of connecting in Philadelphia, the discussions seem largely irrelevant.

American originally sought a contract with the Allied Pilots Association enabling code-shares equivalent to up to 50% of domestic available seat miles, but an initial tentative contract with US Airways reduced the amount to 4% and the eventual memorandum of understanding settled on 15%. Because if you have Philadelphia, who needs it?

Besides more code sharing, the new APA contract also enables more use of regional jets. This could allow American to more efficiently allocate aircraft in Kennedy markets, especially given that air traffic delays have diminished. "American has a wonderful facility at Kennedy but they don't really have a lot of activity there," Mann said. "(American) Eagle never had the right gauge of equipment and the (environment) is more tolerant of hubbing activity now."

Regarding LaGuardia, US Airways benefited from a

2011 deal

with Delta, exchanging 132 slots at LaGuardia for 42 slots at Washington Reagan National. CEO Doug Parker said Tuesday at the JP Morgan conference that "we're really happy with that transaction," which led to more efficient airport utilization for both carriers. "It worked out well," Mann said, yet "following the law of unintended consequences, do they now have perhaps a déjà vu moment, where they might have wanted to withhold a few more slots?"

Delta, the leading carrier at LaGuardia with about 21% of airport capacity, has taken over the former US Airways terminal. It has spent $160 million to connect its two LaGuardia terminals and now operates 271 daily peak-day departures to 63 destinations from LaGuardia. American is the second-largest LaGuardia carrier, with about 15% of capacity, and US Airways probably adds a point or so. New American will control some key LaGuardia markets, including Charlotte, Dallas, Miami and half of Chicago.

At Kennedy, Delta has spent $1.4 billion on a new terminal that is scheduled for a grand opening May 24. The JFK hub has 146 daily peak-day departures to 78 destinations, including 30 international destinations in five continents.

At the JP Morgan conference, Delta President Ed Bastian focused on Delta's effort to catch up in the JFK/Heathrow market long dominated by American and joint venture partner

British Airways

. A deal to acquire 49% of

Virgin Atlantic

and to form a trans-Atlantic joint venture will make Delta a strong No. 2 player in the market.

"The most important corporate initiative we have at Delta is our win in New York strategy," Bastian said. "We've picked up over seven points of overall corporate market share in New York in the last three years, and as we look in 2013, that's continuing to grow."

On another front, Delta is the official airline of the Mets, Yankees and Madison Square Garden. JetBlue is the official airline of the Jets and the Barclay Center, and United is the official airline of the Giants.

Just where will American squeeze into the equation?

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-- Written by Ted Reed in Charlotte, N.C.

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Ted Reed