skynerf

Please forgive me if this has been covered before but it hasn't showed up in my results. I just got back to FSX and learned to navigate by VOR and program the autopilot but it doesn't work quite how I want. I key in the ILS frequency of the destination runway into the gps, switch to GPS from NAV, take-off, switch on autopilot (altitude, VOR hold, airspeed etc) and I can see the aircraft becomes aligned with the runway on my flight instruments yet when I get closer to the destination airport the runway is skewed and positioned perpendicular with the aircraft... I thought that if the aircraft shows aligned with the runway on my instruments it should also be aligned with the actual runway. Am I forgetting something? This is on a boeing 737 aircraft Thanks!