Fight off the Aeropan shock troops is a mission in The Lost Frontier. Phoenix received word from Far Drop about a siege laid on by the Aeropans, so he and Jak set out to fend off the attack and push them back.
Your first target will be an Aeropan commando situated on a flying platform, complete with destructible cover and another platform orbiting the first one with a mounted turret. The commando will throw blasts of dark eco at you while the turret fires larger blasts of energy. The turrets cannot be destroyed by you and will fire even if the commando is hiding behind his cover, though they will blow up if the commando on the main platform is killed. Thus, you should shoot down the commando as quickly as possible to stop the turrets and gain access to the other side of the gap by using the now-cleared platforms.
You will next encounter gladiators. These powerful warriors are larger and stronger than standard commandos, but do not have a ranged attack and are thus an easy target for the Gunstaff, as long as you stay away from them. Proceed to fight more commandos and gladiators until you reach a river, which you have to cross with the use of your eco shield power. Afterwards you will approach Barter's tavern, which has been taken over by an ethereal sub-commander using a device to generate a large sphere of dark eco. The device emits bolts of electricity if you attempt to enter the shield, so use either your own eco shield or eco reflexes as a supplement to avoid them and destroy both it and the commander, as well as the two gladiators guarding him.
Now use the nearby aeropult to access the generator and restart it, followed by sending out Daxter in a tiny weaker version of the eco shield through a hole. Daxter will now have to use the shield like a large ball and roll it down a track plagued with electricity and dangerous holes in the floor, up until you reach an unaware commando at the bottom. Ram into him to relieve him of his platforms, from where you can use Jak again to continue through Far Drop.
Now head for the crane at the plane garage and proceed to fight another sub-commander to gain access to the crane and release the large crate it is holding up. With an aeropult battery in your possession, return to the tavern, bypassing the river by relieving another commando of his platforms, to use the aeropult to launch yourself to another area. From here you can reach an Aeropan camp, guarded by another sub-commander operating a shield generator. Destroy both and any present soldiers, then pick up the bomb and use another aeropult. Now you must again use Daxter and the eco shield power as a hamsterball and direct him through a much longer and harder passage, after which you will use another newly freed platform to access the Aeropan dropship.
Kill the ethereal sub-commander and gladiators guarding the deck, then plant the bomb and exit the dropship to end the siege on Far Drop.