SESGDL From United States of America, joined Jan 2001, 3385 posts, RR: 11 Reply 5, posted (8 years 9 months 1 week 6 days 5 hours ago) and read 1324 times:
Where's that info from? By mainline flights, US leads at BOS, followed by DL, and then AA. Also, DL carries the most passengers at BOS. So it's hard to say who's the largest, they all have their pluses. DL carrying the most PAX, AA serving the most destinations, and US having the most flights.