No, I have made it rather clear that much of the market level public data does not exist yet to demonstrate that DL is moving traffic from other carriers to its LGA operation...... but let me cite what the Port Authority of NY/NJ has posted in their traffic reports.
"Though seat capacity was virtually unchanged, LGA
remained the fastest growing among our airports as
YTD June passenger traffic grew a strong 6.1%. YTD
June domestic passengers grew 5.3%. Domestic
growth leader Delta increased its domestic capacity by
17%, using its newly acquired slots to expand services
to 17 new domestic destinations, including Dallas-Fort
Worth, Miami and Buffalo. American and JetBlue
rounded out the top three with an aggregate net
contribution of 150,000 passengers. The international
sector continued its double-digit drive with growth of
23%, led by Delta's services to Nassau and by
American, Air Canada and new carrier West Jet's
services to Toronto."
http://www.panynj.go...JUN2011_LGA.PDF
Further, there is one market that I personally know about where DL added new service from LGA equivalent to 2/3 of the seats that B6 operated from JFK in the year before. DL also operated in this market from JFK the year before and continues to do so. DL added twice as many seats in the total NYC-XXX market than US pulled out. B6 reduced its seats by about 20% from a year earlier while UA/CO also reduced their capacity in this market by about 25% thus there was a shift in this market from B6 at JFK and UA at EWR to DL at LGA. Net/net is that DL's seat share of the NYC-XXX market went from 25% of the market to 40% of the market and based on average fare information from the year before (which may or many not have changed), average fares from LGA are about 20% higher than they are from JFK.
The data I posted is specific to just one airport and also reflects information BEFORE the summer and BEFORE DL received the 2nd half of the slot swap. In addition, the PANYNJ's report indicates that DL is driving the growth in passenger growth in markets throughout the NE.
So, yes, there is preliminary evidence from the one market that I know about - and which fits the description of the comment from the B6 agents cited on a.net - as well as the PANYNJ data to show that DL is indeed shifting traffic to LGA.
As for why DL "trumped" B6, it is obvious to anyone that understands airline economics that 1. LGA is the preferred NYC airport for local traffic in markets that can be served from LGA AND 2. Hub operators have an advantage over other operators in their ability to compete in the market in that they can sell both local and connecting traffic which allows them to add more seats to the market than a carrier operating on a point to point basis - or with a smaller hub - and increasing the chances of attracting local passengers. There is abundant data in the airline industry to show that the strongest operator at a hub commands the highest fares.
Thus, there very much is evidence to show - even a few months into the slot swap - that DL is using the dynamics of a hub at NYC's preferred airport for short haul traffic to shift traffic from other carriers at other airports - including B6 - to DL at LGA.
DL, like any company should, is doing what is best to increase DL's revenues.... irrespective of whose toes they step on.