I'll just entertain this a bit:

No, regionals will not call within one hour. Here's how it goes:

If you're a DEC: Piedmont and Envoy will call within an hour.

If you're an FO:

Envoy will reply with an automated email saying they are full, thanks, they will keep your resume on file.
GoJet, TSA will reply within an hour and will keep spamming your email until you tell them thanks but no thanks.
Compass will email and say they are done for 2018, get back to them at 2019.
PSA won't get back to you until 4-5 weeks later, depending how your timing works with their (one) person who checks the resumes.
Republic and Endeavor will get back to you within a week and actually schedule things and get the ball rolling.
No clue about SkyWest, didn't bother applying there.