Lack of frames hasn't been the problem as it has opened in smaller markets like DTW, CLE and BNA, where it competes against just one carrier on it's routes.

In ATL, it'd have to compete against Delta and Southwest on BOS-ATL and ATL-FLL. Probably Spirit would end BOS-ATL but even with that assumption, B6 might be estimating weak yields on the BOS-ATL route with the fares it would sell with the fare war of three or more carriers. Southwest is on the route as the alternative to Delta already for business passengers. JetBlue would need not just Delta's marketshare to pull from.