One of the most delay-plagued, congested airports in the world seems like the last place you would want to route lots of passengers who are simply making a connection. But that is what Delta Air Lines Inc. is doing at New York's La Guardia Airport.

Located in the borough of Queens just a few miles from midtown Manhattan, La Guardia has long been a prime gateway into and out of New York, handing 24 million passengers a year with just two intersecting runways and overcrowded terminals, taxiways and gates. Passengers endure delays in exchange for the convenience of proximity to the city, but few would go there simply to switch flights.

Delta is now trying to change that. After acquiring a large block of landing slots and gates from US Airways Group Inc. earlier this year, Delta added more than 100 additional flights a day at La Guardia, switched some flights to larger airplanes and began building a hub...

...Competing airlines and analysts question whether Delta can make a hub operation work at La Guardia, especially since domestic flights are concentrated at La Guardia and international and West Coast flights at JFK.

United acknowledges that Delta will overtake it in domestic market share from New York, but United will still have the largest international market share from its hub in Newark, and the ability to easily make connections at one airport while Delta is spread across two New York airports.

"Newark offers a true connecting hub,'' said Jim Compton, United's chief revenue officer.

La Guardia is a difficult place to connect passengers without major inconvenience. So far this year, La Guardia has had the highest rate of canceled flights in the U.S., according to FlightStats.com, a flight-tracking service. And canceled flights result in 30% of all hours of travel delay for passengers, according to researchers at the Massachusetts Institute of Technology.

"Personally, I would not consider this a good idea," said Vikrant Vaze, a researcher who worked on the MIT transportation studies. Connecting more customers at La Guardia means "a lot of these delays will be substantially magnified because of missed connections."

Delta counters that its changes could reduce delays at La Guardia because it replaced slower-flying US Airways turboprop airplanes with faster jets. Because the number of slots remains the same, there aren't more flights at La Guardia.