ok you need two people get one in a banshee and one a warthog have the person in the banshee go up against the wall have the person in the gunner part of the warthog shoot the banshee and you might be able to fly through. p.s. you can do it with a tank to and please note you need a gaussas warthog.
uhhhhhhhhhh.... and how would this push it into the sign?????