| ACK–BOS | Nantucket – Boston | 3,515 |
| LGA–ORD | New York – Chicago | 1,357 |
| BOS–DCA | Boston – Washington | 1,176 |
| ATL–LGA | Atlanta – New York | 1,157 |
| BOS–ORD | Boston – Chicago | 1,101 |
| LGA–YYZ | New York – Toronto | 1,075 |
| BOS–LGA | Boston – New York | 1,032 |
| DCA–ORD | Washington – Chicago | 978 |
| ORD–YYZ | Chicago – Toronto | 830 |
| ATL–DCA | Atlanta – Washington | 811 |
| BOS–PHL | Boston – Philadelphia | 758 |
| BNA–ORD | Nashville – Chicago | 731 |
| ATL–PHL | Atlanta – Philadelphia | 728 |
| DTW–ORD | Detroit – Chicago | 727 |
| BOS–JFK | Boston – New York | 713 |
| CLT–ORD | Charlotte – Chicago | 706 |
| EWR–ORD | Newark – Chicago | 700 |
| BNA–LGA | Nashville – New York | 682 |
| CMH–ORD | Columbus – Chicago | 673 |
| ATL–EWR | Atlanta – Newark | 645 |
| BNA–DCA | Nashville – Washington | 642 |
| JFK–ORD | New York – Chicago | 629 |
| CVG–ORD | Cincinnati / Covington – Chicago | 628 |
| MCI–ORD | Kansas City – Chicago | 625 |
| ORD–TVC | Chicago – Traverse City | 616 |
| IND–ORD | Indianapolis – Chicago | 614 |
| CLT–LGA | Charlotte – New York | 611 |
| LGA–STL | New York – St Louis | 600 |
| JFK–RDU | New York – Raleigh/Durham | 600 |
| LGA–RDU | New York – Raleigh/Durham | 588 |
| DCA–LGA | Washington – New York | 583 |
| BOS–CLT | Boston – Charlotte | 581 |
| BOS–BWI | Boston – Baltimore | 580 |
| CLT–EWR | Charlotte – Newark | 572 |
| ORD–RDU | Chicago – Raleigh/Durham | 548 |
| ORD–XNA | Chicago – Fayetteville/Springdale/Rogers | 544 |
| ORD–STL | Chicago – St Louis | 539 |
| ORD–PIT | Chicago – Pittsburgh | 538 |
| IND–LGA | Indianapolis – New York | 531 |
| ATL–CLT | Atlanta – Charlotte | 528 |
| MEM–ORD | Memphis – Chicago | 514 |
| CLE–ORD | Cleveland – Chicago | 512 |
| BNA–JFK | Nashville – New York | 509 |
| CVG–EWR | Cincinnati / Covington – Newark | 508 |
| CMH–LGA | Columbus – New York | 508 |
| MSN–ORD | Madison – Chicago | 504 |
| DTW–LGA | Detroit – New York | 490 |
| DFW–EWR | Dallas-Fort Worth – Newark | 489 |
| GRR–ORD | Grand Rapids – Chicago | 483 |
| GRB–ORD | Green Bay – Chicago | 483 |
| ORD–TUL | Chicago – Tulsa | 479 |
| BOS–IND | Boston – Indianapolis | 475 |
| OMA–ORD | Omaha – Chicago | 468 |
| BOS–EWR | Boston – Newark | 464 |
| DTW–EWR | Detroit – Newark | 464 |
| EWR–IND | Newark – Indianapolis | 462 |
| LGA–PIT | New York – Pittsburgh | 459 |
| DCA–IAH | Washington – Houston | 457 |
| ORD–RIC | Chicago – Richmond | 456 |
| CVG–JFK | Cincinnati / Covington – New York | 452 |
| EWR–YYZ | Newark – Toronto | 449 |
| ICT–ORD | Wichita – Chicago | 447 |
| ORD–SDF | Chicago – Louisville | 446 |
| CLT–JFK | Charlotte – New York | 445 |
| LGA–YUL | New York – Montréal | 441 |
| CLE–LGA | Cleveland – New York | 436 |
| ORD–YUL | Chicago – Montréal | 434 |
| ORD–TYS | Chicago – Knoxville/Maryville | 425 |
| BOS–BUF | Boston – Buffalo | 418 |
| BNA–PHL | Nashville – Philadelphia | 407 |
| BWI–ORD | Baltimore – Chicago | 404 |
| BOS–CVG | Boston – Cincinnati / Covington | 404 |
| LIT–ORD | Little Rock – Chicago | 401 |
| GSP–ORD | Greenville/Greer/Spartanburg – Chicago | 395 |
| DSM–ORD | Des Moines – Chicago | 392 |
| CMH–EWR | Columbus – Newark | 392 |
| BNA–BOS | Nashville – Boston | 391 |
| LGA–RIC | New York – Richmond | 390 |
| CID–ORD | Cedar Rapids – Chicago | 386 |
| BOS–RDU | Boston – Raleigh/Durham | 383 |
| EWR–RDU | Newark – Raleigh/Durham | 380 |
| CHS–LGA | Charleston – New York | 379 |
| BOS–IAD | Boston – Dulles | 378 |
| DCA–MSP | Washington – Minneapolis | 378 |
| BOS–CMH | Boston – Columbus | 364 |
| JAX–ORD | Jacksonville – Chicago | 364 |
| CAE–ORD | Columbia – Chicago | 361 |
| BOS–MIA | Boston – Miami | 357 |
| EWR–YUL | Newark – Montréal | 357 |
| DCA–IND | Washington – Indianapolis | 357 |
| ORD–PWM | Chicago – Portland | 356 |
| CLT–DCA | Charlotte – Washington | 355 |
| CVG–PHL | Cincinnati / Covington – Philadelphia | 355 |
| ALB–ORD | Albany – Chicago | 351 |
| GSO–LGA | Greensboro – New York | 351 |
| IND–JFK | Indianapolis – New York | 350 |
| MDT–ORD | Harrisburg – Chicago | 349 |
| ORD–ORF | Chicago – Norfolk | 344 |
| BOS–PIT | Boston – Pittsburgh | 344 |
| BNA–RDU | Nashville – Raleigh/Durham | 342 |
| DJT–LGA | West Palm Beach – New York | 338 |
| ORD–ROC | Chicago – Rochester | 336 |
| ILM–LGA | Wilmington – New York | 329 |
| DCA–STL | Washington – St Louis | 326 |
| EWR–SDF | Newark – Louisville | 325 |
| JFK–PIT | New York – Pittsburgh | 325 |
| PHL–RDU | Philadelphia – Raleigh/Durham | 324 |
| EWR–PIT | Newark – Pittsburgh | 324 |
| LEX–ORD | Lexington – Chicago | 324 |
| DCA–EWR | Washington – Newark | 323 |
| DTW–PHL | Detroit – Philadelphia | 322 |
| BUF–ORD | Buffalo – Chicago | 319 |
| GSP–LGA | Greenville/Greer/Spartanburg – New York | 318 |
| ORD–PVD | Chicago – Providence/Warwick | 316 |
| LGA–ORF | New York – Norfolk | 311 |
| AVL–ORD | Asheville – Chicago | 310 |
| ORD–SYR | Chicago – Syracuse | 308 |
| LGA–MEM | New York – Memphis | 305 |
| BDL–ORD | Hartford – Chicago | 303 |
| CLE–JFK | Cleveland – New York | 302 |