Hi Aliza,
Being Spanish, I've flown quite often in TGA, especially in SCW campaigns. Both my grandfathers fought for the Republican side and most of my relatives went into hard times when the war was lost, so I feel happy to pay a virtual hommage to them flying for the Spanish Republic.
Moreover, thanks to the wonderful maps by RedEye and Jir, I am able to fly over the city I live in and the places I daily drive to work or on holidays.
Concerning TGA campaigns, I agree with jpten. Apart from the Spanish Civil War, this module offers an unexplored world of classic passenger aircrafts and air races. I wish some people made such types of missions. Just for fun, I made a pair of alternate missions about sky pirates using seaplanes and hiding in desert islands (yes, 'Porco Rosso' style).
Regarding your problems with 'Escape' Monty's campaign... did you uncheck 'No instant success' in the difficult settings? I've just tried the first mission in the campaign (the one in which you have to drive a car), and it seems that there is no target object when you reach your objective, so you'll never obtain a 'Mission complete' message. If 'No instant success' is deactivated when starting the campaign, you can press Esc at the end of the mission and you will be able to skip to the next mission. Otherwise, I suppose that you will be stuck in the first mission since you didn't fulfill any targets.
Finally, in some missions I've also experienced AI refusing to takeoff, as you mention about the Bulldogs. I don't know the exact reason, but I managed that AI finally started they run by using Communications (TAB key) > Wing (or appropriate section) > Navigation > Start engines (or something similar, I don't remember the precise pathway). Sometimes AI is especially dumb.