GSA City Pair Search The contracts really seem to vary out of MSY

ATL - FL
BWI - WN (seeing WN on contract fares is fairly new)
IAD - UA
DCA - US
DTW - DL
EWK - AA
JFK - B6
LAX - UA
LGA - DL
MSP - DL
ORD - AA
ORF - US
ONT - AA
SAN - UA
SFO - AA
SLC - DL

Depending on the city/cities you fly to, your carrier will vary.