David Vega

Michael,
 
Have you checked your joystick, or controller calibration?  Suggesting this only because the apparent behavior matches what happens when on the jet is on autopilot and the pilot manually moves the yoke.  
 
Regards

There is a way to manually build a transatlantic route using the FSX Flight Planner, but it is very tedious and time consuming.  There are ways to get the route into FSX without using the FSX Flight Planner.  
 
Like Silicus said, for a realistic route, check www.flightaware.com.  For example, today I see that British Airways flight 9153 is on its way from KMIA to EGLL, using:  
 
VALLY NUCAR A699 LOUIZ A699 SUMRS M204 BEXUM M204 SOORY 4300N 05000W 4700N 04000W 4900N 03000W 5000N 02000W SOMAX ATSUR GAPLI UL620 GIBSO M17 BILNI
 
you have two freeware options:
www.simroute.com.  Click on "Generate Routes."  Enter KMIA on Departure, and EGLL on Arrival, and then copy/paste the route from flightaware in Route.  Click on the Generate Route button and you will see a page that has all kinds of information about the route.  In this page you can select the aircraft type, estimated True Airspeed, and the format you want to use to save the flight plan (FSX, FS9, etc.)  You can even see your route plotted in a map at the bottom of the page.  Once you select the flight plan format, cilck on Download Flightplan and it will download a flight plan file to your computer.  You can then load this flight plan from FSX.   www.vroute.net.  Download their "standard" or freeware program, and use it in a similar fashion as above, to generate a new route.  A good thing about this program it gives you access to lots of ready-to-use routes, but you can also make your own.  Like simroute.com, you can use this program to save a flight plan in FSX format.   Hope this gets you going.  Let us know if you are still interested in using the FSX Flight Plan to manually create a transatlantic route.  It will require good knowledge of lat/lon, other helper web sites, and tons of patience.  
 
Regards,