but you need them to get 100%. However, I found that particular Zero mission rather easy. I had some serious problems with the first one, though (where you had to protect those poles. Hitting toy-planes with an MG is not as easy as it sounds). But I'll give you a tip regarding te suply lines mission:
take the plane, and land behind the couriers. Then just fire at them, they shouldNät have time to escape (make sure that you pull the right trigger and push the analog stick up as soon as you start fireing, else they'll escape). If you do them that way (the first van and the bike courier are easy to take out, as the drivers will get out off the car/off the bike, and you can easily finish them with your machine gun). The hardest one is the Motorbike courier, as he will accelerate and drive away, while the other guy fires at you.