1.) Boston sees every Delta subsiduary (Mainline, Express, Shuttle, Connection).
2.) BOS, LGA, and IAD see every US Airways subsiduary (Mainline, Shuttle, Express, MetroJet)
3.) SNA, LAS, PHX, LAX, SEA, SFO, SAN
And Flyf15, TWAneedsHELP I think mean Delta Connection carriers, as most people tend to just put all the connection carriers (ie Comair, ASA, Trans States, Business Express, SkyWest, AC Jet for Delta) into one category of subsiduary.