Basically what A4s (the all knowing) said. We also have a Corporate flight department that fly Lears and do progress to 'The Line' if they decide to.
The 'feeders' are similar in dynamics to 'regionals'. I will caviot (spelling) what A4s said in they don't 'normally' use FEDEX callsigns but Mountain Air, Empire, etc. Mountain Air Cargo flies our feeder stuff here in graceland but they vary by location.
http://www.airlinepilotcentral.com/airlines/cargo/mountain_air_cargo.html
They also normally have different ops, flight planning and such from us. A/C may be parked on same ramp but they feeder folks are usually in a different building or office/lounges. But at the smaller stations you would be hard pressed to not see and chat with them. We do have some big egos that ignore those folks and treat them like lessers. But life is too short; but me being a terminal 0-3 and 1/2 have never particularly cared about rank and heiarchy and my FITREPS reflect it.
Most folks flying OUR feeders like the schedules, benefits, well maintained A/C, etc and aren't using it as time builder. Or so it has been the case with those that I have bullshitted with. YMMV.
Air Fleet
71 Airbus A300-600s
56 Airbus A310-200/300s
13 ATR 72s
26 ATR 42s
79 Boeing 727-200s
1 Boeing DC10-10s
6 Boeing DC10-30s
57 Boeing MD10-10s
12 Boeing MD10-30s
57 Boeing MD11s
10 Cessna 208As
242 Cessna 208Bs
24 Boeing 757-200s
More facts:
http://about.fedex.designcdt.com/our_company/company_information/fedex_express