The quick answer is "yes".  Depending on the complexity of the mission however, actually making the changes may take some effort.  

Using Mission Builder you can change the takeoff/landing base location easily but you will probably need to move and adjust all of the waypoints for not only the Player aircraft but all of the AI planes as well.  Plus, ship waypoints and infrastructure locations may need to be changed depending on the mission.

Depending on how close the other base is you can highlight and drag all of the objects together as a single unit to the new location, saving you much time and keeping the physical relationships of object to object intact.  However, this becomes problematic if the distances are too great.

That said, I would encourage you to modify existing missions and create your own, as mastering the Mission Builder adds an entirely new dimension to the game.  One word of warning before you begin.  Make sure to back up any stock missions you plan to modify and put them in a safe place so that if you mess one up entirely, or want to replace it you can do so easily.

Coyote has more experience than I . But I too subgest you get Coyotes Tuturial on Mission Building and learn to build your own.
Its a heck of lots of fun!

James007

PS If you find my response a bit repeticious is because by accident Coyote and I where writting our post at the same time. Only he posted his first.

You can find Coyotes Tutorial Here:http://www.simviation.com/cgi-bin/yabb/YaBB.cgi?board=cfs2;action=display;num=11...