Grand Theft Auto: San Andreas/Green Goo

With the jetpack you fly to the train, shoot the soldiers and one of the boxes contains something, get it and retrieve it to Truth. It's very simple.

Tips

 * Be sure to have a good SMG or machine pistol so that you can shoot while flying.
 * Try to land on the back of the train and then you can concentrate more on aiming.
 * A straight-line route back to your airfield from the train is likely to cross the restricted airspace at Area 69. The SAMs here WILL open fire on your jetpack although the damage is less than you might think (approximately 50% of your health/armour per hit).

Rewards
Asset: Verdant Meadows Airstrip (Max $10,000)