No 747s at LGA, the runways are too short. LGA also did not handle 707, DC-8 or 720 aircraft. National (1st), American, and others all flew DC-10-10s into LGA, and DL L1011-1 and later 767-200/300, but these aircraft need less runway than a 747. As a matter of fact, one of the design criteria of the DC-10/L1011 was its ability to land at LGA. Back in the early 70s, it was much more common to see wide-body aircraft on domestic routes; for example, National was all wide-body between NYC and Florida at one time. Hubs and increased frequencies have of course changed all of that. Also, remember that LGA is limited to flight of approx 2000 miles or less - you can fly from LGA to Denver, for example, but not to Salt Lake City (much to DL's annoyance!).