Here are the September T100's (onboard loads) for Frontier's eastern division and for select competitors. As always, remember that onboard loads are only half the picture when trying to judge the relative financial performance as they tell us pretty much nothing about fare and traffic composition.

Routes primarily served by Airbus / Ejet
(Note that the thru-passenger undercount issue was particularly pronounced on some MCI routes as noted below)
94.8% ….. MKE ….. SAN
93.0% ….. MKE ….. SEA
93.0% ….. MKE ….. DEN
92.9% ….. MKE ….. LAS
90.9% ….. MCI ….. SEA ….94.3% one direction, 80.7% the other
87.5% ….. MCI ….. SFO ….94.3% one direction, 80.7% the other
81.4% ….. MCI ….. BOS
80.5% ….. MKE ….. MCO
80.2% ….. MKE ….. PHX
78.3% ….. MCI ….. MSY
78.1% ….. MKE ….. DFW
77.0% ….. MCI ….. DCA
75.7% ….. MKE ….. LGA
73.9% ….. MCI ….. LAX
73.8% ….. MKE ….. MCI
72.6% ….. OMA ….. DCA
70.7% ….. MKE ….. BOS
69.8% ….. MCI ….. LGA
67.7% ….. MKE ….. SAT
67.1% ….. MCI ….. AUS ….74.8% one direction, 59.5% the other
62.2% ….. MKE ….. DCA
58.4% ….. MCI ….. SAT ….64.5% one direction, 52.4% the other
50.8% ….. MCI ….. MSP

Routes primarily served by ERJ
91.0% ….. MKE ….. MSP
90.5% ….. MKE ….. PIT
87.4% ….. MKE ….. PHL
86.5% ….. MKE ….. EWR
85.7% ….. MKE ….. BNA
81.8% ….. MKE ….. OMA
79.9% ….. MKE ….. BDL
79.7% ….. MKE ….. IND
78.0% ….. MKE ….. STL
77.5% ….. MKE ….. DSM
76.5% ….. MKE ….. RHI
76.3% ….. MKE ….. BKG
74.8% ….. MKE ….. GRR
74.8% ….. MKE ….. CMH
72.2% ….. MKE ….. FNT
71.2% ….. MKE ….. CLE
70.9% ….. BKG ….. AUS
69.2% ….. MKE ….. MSN
65.5% ….. MKE ….. SDF
64.5% ….. MKE ….. DAY
62.9% ….. MKE ….. GRB
59.0% ….. MKE ….. MBL
47.9% ….. MKE ….. ATW

American
74.2%.....MKE.....DFW

AirTran
96.9% ….. MKE ….. SFO
96.5% ….. MKE ….. SEA
87.3% ….. MKE ….. LAS
84.9% ….. MKE ….. LAX
83.7% ….. MKE ….. FLL
76.6% ….. MKE ….. MSP
73.1% ….. MKE ….. LGA
71.8% ….. MKE ….. ATL
71.4% ….. MKE ….. MCO
68.8% ….. MKE ….. RSW
68.4% ….. MKE ….. TPA
63.1% ….. MKE ….. DCA
62.4% ….. MKE ….. BOS
59.7% ….. MKE ….. DEN
51.1% ….. MKE ….. BWI
45.3% ….. MKE ….. CAK
40.1% ….. MKE ….. SRQ
23.5% ….. MKE ….. DSM

Skywest operating as FL* (operated through 9/7/11)
79.9% ….. MKE ….. PIT
76.1% ….. MKE ….. STL
74.1% ….. MKE ….. CAK
71.1% ….. MKE ….. IND
67.8% ….. MKE ….. OMA
62.2% ….. MKE ….. DSM

Southwest
87.5% ….. MKE ….. LAS
85.8% ….. MKE ….. PHX
69.7% ….. MKE ….. DEN
69.2% ….. MKE ….. MCI
69.0% ….. MKE ….. BWI
66.9% ….. MKE ….. MCO
57.5% ….. MKE ….. TPA
46.5% ….. MKE ….. STL

DL* at Kansas City
86.4% ….. MCI ….. BOS
79.7% ….. MCI ….. LAX
77.8% ….. MCI ….. MSY
75.7% ….. MCI ….. AUS
71.8% ….. MCI ….. LGA
57.2% ….. MCI ….. CMH

DL* at Omaha
71.9%.....OMA.....DCA

I'll see if I can get DEN posted fairly soon for those interested.