Just to inject a little actual information into this discussion.
Here are the frontier stats for JULY from DoT:
On Time 5,774 71.37% N/A N/A
Air Carrier Delay 474 5.86% 32,254 21.92%
Weather Delay 25 0.31% 1,254 0.85%
National Aviation System Delay 1,151 14.23% 57,740 39.23%
Security Delay 0 0.00% 0 0.00%
Aircraft Arriving Late 614 7.59% 55,927 38.00%
Cancelled 33 0.41% N/A N/A
Diverted 19 0.23% N/A N/A
Total Operations 8,090 100.00% 147,175 100.00%
Sorry for the formatting.
Here is the Southwest data for the same period:
On Time 83,575 73.54% N/A N/A
Air Carrier Delay 8,805 7.75% 489,665 30.06%
Weather Delay 797 0.70% 57,282 3.52%
National Aviation System Delay 4,602 4.05% 198,561 12.19%
Security Delay 37 0.03% 1,033 0.06%
Aircraft Arriving Late 14,595 12.84% 882,517 54.17%
Cancelled 839 0.74% N/A N/A
Diverted 400 0.35% N/A N/A
Total Operations 113,650 100.00% 1,629,058 100.00%
Note that Southwest cancelled flights at nearly double the rate as Frontier, although the impact was probably much less since Frontier does not offer the frequency Southwest does.