So basically, the Snowspeeders hovered sround, waiting for the AT-AT to attack them?
18.104.22.168 Charges. If a unit is charging a stationary unit, then move it straight ahead to its point of impact. If two units are charging each other then move each equal distances straight ahead to the point of impact. The result will be either a flank charge, head to head charge, or charge to the rear. Which of these occurs depends on the orientation of the two units prior to charge movement. See Figure 6 for illustrations of some possibilities
The Snowspeeder charged up against the AT-AT.
Like Froz said, the ground forces on Endor used stealth to destroy the bunker and so did the two squadrons of Starfighters that striked the first Death Star.If they had actually fought a head-to-head battle against the Death Star, they wouldn't have been trying to sneak past the defenses.