The thing 121 guys should really take note of is how hard most these Fractional crews work . An 8 on 6 off schedule after having worked 9 to 12 days a month of 1 or 2 leg days at your airline is lots more work. Plus most the fraction companies are real good at using you the full duty day followed by a realitvly short layover. An airport friend who does this type work said he had no doubt an airline guy could do the job but beware of what you are getting into .