Originally Posted by
eponymous_coward
It would be extremely irresponsible to allow a carrier who dominates LGA like AA or DL to have access to more slots when the entire point of the transaction was to have a non-dominant carrier get access to LGA (AS and VX are about as non-dominant at LGA as you can get). It would also be irresponsible to allow AS to sell to, say, WN, allowing them to dominate the DAL-LGA market. Once you eliminate AA/DL/UA/WN... who's left? B6? (I can't imagine NK or G4 are going to be interested.)
OTOH, AA and/or DL will serve smaller cites from LGA that no one else will serve. Adding WN or another LCC/ULCC will only add service to a route that already has service. While it makes for lower fares from those city pairs, it doesn't help those living away from major markets.