Date: 201902
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Communication Breakdown; Time Pressure
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Procedure; Human Factors
Primary problem: Procedure

Narrative: At XA05 I received a call from Crew Scheduling regarding a DH (deadhead) from ZZZ1 to ZZZ. Report time was XC10 (2H 5M call-out). I was to be operating a return leg either to ZZZ1; or a leg to ZZZ2 with a DH back to PHX. I live over an hour from the terminal; so I got rolling.I took about an hour for my schedule to be updated; I would be operating Flight X from ZZZ to ZZZ3. I looked more closely at my updated schedule and my DH arrival time was XE19; and Flight X's departure was XE35 (a mere 16 minutes later). I called crew scheduling at XB05 to make sure they were aware of the time-crunch; and that there was no way I'd be able to make that departure time; and to make the other crewmembers aware. Crew Scheduling stated that departure time was XF35; and that I should have 1H 15M; and that it shouldn't be a problem. I asked them to double-check their times; and after a brief hold they realized that the XE35 departure was indeed correct. They informed me that other reserve crewmembers were also commuting in; and that they would have to delay the departure for all of us. The reserve Captain was also on my DH; and upon landing we rushed over to the departure gate. The flight was delayed an additional 20 minutes to accommodate our late arrival; and everything seemed to be working normally (other than us being delayed). The flight attendants had already boarded when we arrived at the gate. Dead-heads; non-rev's and delayed passengers were in-line at the gate agent kiosk. Ops normal for a delayed flight. Captain checked over the release paperwork for irregularities; and immediately recognized that the TLR (Takeoff/Landing Report) data was missing. He asked for them to print a new release; and we headed down to perform pre-flight duties. After my exterior pre-flight I quickly introduced myself to the FAs (Flight Attendant) as I stowed my luggage. They were stressed because catering had not been over; there were still old meals in the service carts; there was no ice; etc and the Gate Agent was anxious to board. Again; ops check normal for a delayed flight.The original departure time had been delayed for over 8 hours; so the majority of the passengers had already been re-assigned. Our flight included just a handful of passengers who were still waiting to get to ZZZ3 (it ended up being only 14 people); so boarding was over in a flash. We quickly worked through our preflight duties; and we were up and out as quickly as we could be. We were in normal cruise at FL340 with 120 knots of headwind. I was PF (Pilot Flying); and since I knew that we were light I checked the QRH cruise tables and saw that FL380 was optimum for our weight. I asked [the] Captain if he would check the winds up higher in the weather packet; and ask ATC for any ride reports. Everything suggested that we climb higher; so [the] Captain sent our Dispatcher a free-text to obtain an outside opinion. Their reply text indicated that there should be no problem with FL380; but also had the text 'there are no PAX; correct?' We were both puzzled at the question. After some back-and-forth [the] Captain double-checked the Dispatch Release; and sure enough; Remarks 'Operated under 14 CFR Part 91'. We couldn't believe it. [The] Captain replied that we had 14 passengers on board; and apart from a fuel question we received no further communications from Dispatch regarding the situation.The oversight of these remarks on the Dispatch Release is 100% our fault; no question there. I guess we fell into the classic pitfall of being rushed. I can say with confidence that we were not hasty or abbreviated in our pre-flight preparation in any way. We verified everything in the logbook; checked all the NEFs (Non-Essential Equipment Furnishing); found TLR data to be missing and addressed it. I even sent the takeoff data three different times so it was as accurate as possible. Somehow those 6 words on the Dispatch Release made it passed both of us. I know all of the members of our organization worked in a fast-paced dynamic environment; but how can our operational control center and flight coordinator be of the understanding that we are operating a non-revenue repo-flight; and everyone else involved proceed with 100% confidence that we are operating a revenue passenger flight? An oversight was made on our end; but there was unquestionably a breakdown of communication elsewhere that left an entire team of people totally in the dark. As a new First Officer; it's a good learning opportunity that I will carry forward with me in my career.




Synopsis: EMB-175 First Officer reported operating a delayed flight with passengers even though the Dispatch Release indicated the flight was to be operated as a ferry flight.