B737-700 FLT CREW PROGRAMMED THE FMC TO THE WRONG DEST. AFTER AIRBORNE; ATC QUERIED THE FLT CREW ABOUT THE ROUTING; AND THE FLT CREW BECAME AWARE OF THE ERROR.

Narrative

DAY 3 OF A 3-DAY. UNSCHEDULED OVERNIGHT; MUCH SHORTER THAN SCHEDULED. DID NOT SLEEP WELL; XA30 LOBBY FOR AN EVENING TRIP. FLEW 1 LEG; 1 HR 40 MIN GND TIME; DEADHEAD (FO FLEW LEG); 1 HR 40 MIN GND TIME. SO; AFTER BEING ON DUTY 6 HRS WE WERE RESUMING SEQUENCE TO ZZZ1. EXCELLENT FO; THIRD DAY OF SECOND TRIP TOGETHER. PREFLT CHKS NORMAL. AS CAPT; I EITHER FAILED OR DID NOT NOTICE RTE IN FMC WAS TO ZZZ2. FLY THAT RTE SO OFTEN; LIKELY WOULD NOT HAVE REALIZED WRONG RTE IN BOX; BUT EITHER WAY; MY FAULT FOR NOT CATCHING WRONG PROGRAMMING. FLEW THE DEP PROGRAMMED IN BOX. AT APPROX 17000 FT; ATC QUERIED IF WE WERE ON THE RTE. ATC GAVE US A RADAR VECTOR VOR. GAVE DIRECT VOR THEN SWITCHED US TO CTR; WHO GAVE US VECTOR; THEN DIRECT VOR. POOR SLEEP; INTERRUPTED DAY; 5 HR GAP BTWN FLTS CONTRIBUTED TO FATIGUE AND LACK OF SITUATIONAL AWARENESS; BUT DO NOT ACCOUNT FOR MY LACK OF VERIFICATION OF FMC. HOPE I WOULD HAVE CAUGHT ERROR; BUT NOT SURE AS THIS FLT TO ZZZ2 IS A VERY COMMON RTE. WE OFTEN BRIEF WHAT WE NEED TO (AS WE DID BRIEF AND HAD CORRECT CHARTS OUT) BUT FAIL TO SEE WHAT IS REALLY IN FRONT OF US. OVERCONFIDENCE IN A GOOD FO CAN ALSO LEAD US DOWN THE PATH. TRUST BUT VERIFY IS WRITTEN FOR A REASON. 1) TRUST BUT VERIFY; EVEN THE BEST FO'S MAKE MISTAKES. 2) BE EXTRA VIGILANT ON LONG; INTERRUPTED DAYS THAT TAKE US OUT OF OUR NORMAL CADENCE/PATTERNS. 3) BE MORE AWARE OF EFFECTS OF FATIGUE ON PERFORMANCE.