VERY, VERY good question!

Some airlines do, some don't. It is common for newbies to look only at the hourly pay scale without understanding the work rules that determine HOW that payscale is applied...the actual hours for which you get paid can vary dramatically between companies, make sure you understand the companies rules before you accept a job.

I have personally experienced as high as 400% difference between regionals in delay situations and my current company usually pays 150% more than my last employer...it adds up at the end of the month.