LGA gas air traffic control problems simply due to the volume of takeoffs and landings. For example, if my memory serves me correctly, between 3:00 p.m. and 4:00 p.m. the airport can support about 45 takeoff and landings, but the airlines have scheduled 33% more with 60 takeoff and landings.
In regard to yield, LGA Customer Service personnel recently told me that LGA has high yields and JFK very poor yields, which is part of the reason JetBlue is such a low RASM carrier.
LGA station operations are superior and the station regularly ranks at or near the top of US Airways operational statistics.
In addition, Doug Parker recently indicated the Shuttle is profitable.
Regardless of what you think of her, Loretta Bove does a good job as the Managing Director, she is very highly thought of by key personnel in Tempe, and US Airways' LGA operational statistics speak for them self.
Regards,
USA320Pilot