Originally Posted by
monitor
Incorrect information.
At LGA, DL uses three terminals. The third is the old Marine Terminal (now called Terminal A) where flights to Chicago and (apparently important for this OP) DCA flights operate. The change from C or D to A is a slow, brutal bus ride which can take much too long and IMO is something clearly to be avoided.
In addition, I consider any itinerary with a connection at LGA to be complete madness. The delays and IROPs are so prevalent that there are too many days when the arrivals and departure boards looks like some sort of stupid mish-mash. Yes, I use it for O&D but I know to make allowances for LGA since its sheer convenience to the City (15-20 minute cab ride to my apt) makes up for the other nonsense.
Sorry, I missed that OP would be using shuttle flights, which IIRC aren't normally offered as connections. Also, I've heard that DL flights will be moving out of MAT, which certainly is a long and infrequent bus ride away from the rest of LGA.
However, I stand my my opinion that US connections at PHL are to be avoided for both the airline and the airport.