Mon, Nov 12, 2018 (2 a.m.)
| Domestic airline | Passengers | Average daily flights | Cities | |
| 1 | Southwest Airlines 2702 Love Field Drive Dallas, TX 75235 214-792-4000 • southwest.com | 13,564,549 | 194 | 56 |
| 2 | American Airlines 4333 Amon Carter Blvd. Fort Worth, TX 76115 800-433-7300 • aa.com | 3,404,074 | 39.1 | 9 |
| 3 | Delta Air Lines 1030 Delta Blvd. Atlanta, GA 30354 404-715-2600 • delta.com | 3,126,139 | 53.5 | 29 |
| 4 | Spirit Airlines 2800 Executive Way Miramar, FL 33025 954-447-7920 • spiritair.com | 3,118,310 | 34 | 21 |
| 5 | United Airlines 233 S. Wacker Drive Chicago, IL 60606 877-624-2660 • united.com | 3,009,203 | 31.2 | 8 |
| 6 | Allegiant Air 1201 N. Town Center Drive Las Vegas, NV 89144 702-505-8888 • allegiantair.com | 1,800,769 | 22.3 | 57 |
| 7 | Frontier Airlines 7001 Tower Road Denver, CO 80249 720-374-4200 • flyfrontier.com | 1,730,956 | 21.4 | 23 |
| 8 | Alaska Airlines 19300 International Blvd. Seattle, WA 98188 206-433-3200 • alaskaair.com | 1,694,782 | 10.4 | 4 |
| 9 | JetBlue Airways 27-01 Queens Plaza North Long Island, NY 11101 718-709-2202 • jetblue.com | 991,942 | 12.9 | 4 |
| 10 | Hawaiian Airlines 3375 Koapaka St., Suite G-350 Honolulu, HI 96819 808-835-3700 • hawaiianair.com | 371,076 | 2.6 | 1 |
| 11 | Sun Country Airlines 1300 Corporate Center Curve Eagan, MN 55120 651-681-3900 • suncountry.com | 212,791 | 2.8 | 1 |