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.