I can think of a few good ones:
Pinnacle: "Ready to Strike!"
Mesa: "Sucks"
Comair: "Violating our pilots' contract daily and it shows!"
Delta: "We loves us some flyin' and it be showin' like a motherf'er"
---For those who are not in the 'know':
YouTube - Delta Airlines Ebonics Commercial
NWA: "V1, Merge, V2..."
GoJet: "Stabbing our fellow pilots in the back to get you to your destination since 2004"