I've just completed the "Air Show" mission in campaign two, referred to as C2M2 in the H&D2 walkthrough, and had a quick point to make.
It mentions that:-
"I hate this mission. It is unforgivably stupid, and it didn't have to be. The basic concept isn't bad at all; certainly not in a class with some of the other missions in the game. It could have been a perfectly valid mission, of a somewhat no-brainer variety, if it weren't for one irredeemably stupid thing they did to it.
You'll see what I'm talking about when we get into it....."
...."The mission starts with a rather pointless cut scene involving aircraft. I guess it's a warning. The central fact of this mission is those two Messerschmitt fighters.
Might as well get this out of the way right off: the planes are the stupid part I was talking about. Not because they attack you, though there's no logical reason they should - you're in a German truck, after all, and the only men visible are wearing German or Italian uniforms - but because they don't, and yet they do. "
"This is what I mean: as long as you stay with the truck, the airplanes will not bother you. They'll roar by overhead in a very menacing way, but they never ever strafe the truck. Anyone on board the truck is totally safe from their efforts. "
It's possibly not as stupid as he makes out.
The reason the planes don't intercept the truck is because the truck has a flak-cannon on board. They will
intercept the Jeep if you still had that carried over from the previous level, as the Jeep only has a smallish machine gun.
The only reason I know that is, at the first enemy site you come to, there's a large rapid-fire machine-gun type weapon, and if you get onto that, although it will not damage the planes (no matter how hard you try, unless I'm a terrible shot!) the planes will still NOT strafe you while you're sitting on that gun. They'll just continue to circle you. Get off the gun, however, and the planes will resume strafing you again.
Personally I only read that walkthrough after I completed the level (in "Lone-Wolf" mode), and only had the Jeep, lol! I'll tell you how I did it:-
At the first enemy camp you get to, use your sniper rifle or your Jeep's machine gun to quickly pop off the two enemy soldiers. The two Messerschmitts (planes) will be continually circling and strafing at you, so you need to act quick. So, after you killed those two soldiers you can get off the Jeep and search the site and find four bazookas. With a bit of practise you can seperately bring down each Messerschmitt using the bazookas....
...The trick is to wait for a Messerschmitt to come right up to you and then, using the bazooka eye-sights (ie. by pressing the "End" button on your computer keyboard), make sure the Messerschmitt is in the lower box 'viewfinder', and then aim it up slightly (just a touch), and fire it when the Messerschmitt is right up close (ie. nearly filling the viewfinder). You'll know when you hit the Messerschmitt properly as the the back of the plane will start leaving a trail of black smoke. The damaged plane will then fly off, and you wont see it again. Repeat with the other Messerschmitt.
This will leave the rest of the level with less of a headache. You'll need to dismount when you get to the second enemy camp anyway, leaving you vulnerable to the strafing Messerschmitts, so getting off the Jeep/Truck and using the bazookas right off at the start makes sense. Maybe with the Truck, after you've killed the first two soldiers, you can drive up to the bazookas, grab a bazooka and then get back on the Truck again to take your shot at the planes, so that the Messerschmitts don't fire at you while you're taking your shots at them.
It's quite a good level, although frustrating when you figure out how to get past certain parts!