Here's a snapshot from the week of October 22 - it's not perfect due to seasonal adjustments, but it's more or less accurate.

WN: 90+ peak day departures

UA: 37 peak-day departures (4x

CLE, 5x

DEN, 6x

EWR, 4x

IAD, 6x

IAH, 11x

ORD, 1x

SFO)

DL: 34 peak-day departures (8x

ATL, 3x

CVG, 6x

DTW, 1x

JFK, 4x

LGA, 3x MEM, 6x

MSP, 3x

SLC)

AA: 28 peak-day departures (3x

DCA, 9x

DFW, 3x

LAX, 4x

LGA, 1x

MIA, 8x

ORD)

9K: 26 peak-day departures (4x CGI, 3x IRK, 6x MWA, 3x OWB, 4x TBN, 6x UIN)

US: 17 peak-day departures (6x

CLT, 5x

PHL, 3x

PHX, 3x

PIT)

3E: 17 peak-day departures (2x

BRL,

F9: 4 peak-day departures (1x

CUN, 3x

DEN)

AC: 2 peak-day departures (2x

AS: 1 peak-day departure (1x

SEA)

The order isn't the same by capacity. For example,

UA only has a single mainline departure (1x

SFO), whereas

AA has 25 of its 28 flights on mainline (3x

DCA is on

MQ CR7s). Obviously Cape Air's 26 Cessna departures are also far less capacity than US's mix of 17 mainline and regional departures.

[Edited 2012-09-26 10:58:54]