Ok, one question: how on earth am I going to pass this one?

As soon as I reach the planet, I'm surrounded by missiles, and I run out of decoy...

50 times already, I think. This is NO FUN at all!!!

Which difficulty are you playing at? Also look in the middle of the town. On your radar there's a ground mounted missile turret (it might be either Orange or grey... don't remember at the moment). Take that out ASAP as soon as you get there.

Switch throug targets with "T" immediately and send an IR-missile towards every single turret you can find, as fast as you can. While you're doing so, don't push "E" for every single alarm. Keep an eye on your radar to see where the missiles are coming from and change directions often. Use your afterburners to keep the missiles on distance. Start to shake them after you've taken out the turrets. If this won't work (on harder difficulties) try to fly near the ground. Once you've taken out the turrets, get into a steep climb to gain heigth (with afterburners), spam decoys until the alarm stops and take out the fighters.

Flying near the ground helps a lot. You don't get "surrounded" by missiles. At least they're just coming from the sides. Some missiles even hit the ground. And the enemy fighters have some problems as well. They love to attack you from above, which forces them to gain some height after some time. They can't attack you when there noses are pointing upwards ;)