I've been wondering the same thing and even alluded to it on the ASA-Skywest merger thread.

We had a recruiter jumpseat with us a few weeks ago, and I asked him about hiring plans past May, and he said they didn't like to plan that far in advance. But ASA has known since at least January that they were hiring 40/month thru May. Then Skywest extended their hiring window to '08, but nothing yet for ASA. We're losing ground ops to Delta in June. SW has opened a small reserve base in ATL. Some of the new ramps have the Skywest name on them instead of ASA.

Also May lines have shrunk by at least 10, and a lot of the high block time has been reduced. Plus the aforementioned 50 seat flying going to Comair, and the 2-70 seat deliveries temporarily put on hold. Near as I can tell, they're about 90 pilots short on Capt and F/O sides on the 50 alone, supposedly the pilots are just about out of training.

Anyway, it's all slightly suspicious, you think they'd announce hiring thru the rest of the year at least, since they've had a lot of attrition.