Originally Posted by
channa
I tend to see this sort of thing on PMCO-operated leisure market flights (e.g, Caribbean) as well.
I guess they use the seat for pilot rest and avoid having to pay for hotel/per diem for an overnight.
The cost of two hotel rooms and per diem in almost all cases would not be the deciding factor. Factors like gate/parking areas for the overnight aircraft are probably what drives sCal to use 3 man crews on the 737. The addition of an IRO to those flights allows the company to fly the pilots over 8 hours scheduled(actual time in the air, not duty day).
Earlier in the thread a poster commented on seeing a pilot sit up front with the pilots. That was likely a pilot commuting to or from work. Pilots can sit in the cockpit jumpseat(s) at the Captains discretion. That pilot could also have had a positive space pass for DH, training, ect. and took the jumpseat to allow a non-revenue passenger to have a seat in the cabin. Flight attendants are not allowed
to use cockpit jumpseats for any type of travel. If the aircraft has extra FA cabin jumpseats Flight Attendants can use those for commuting. At the current time pilots are not permitted to use cabin jumpseats for any purpose.