Set up shop on a vantage point, such as the base of the rock ridge in front of the Hoover Dam visitor center or the tower behind the stage upon which Kimball is delivering speech, and snipe him with a long ranged weapon.
Sabotage Bear Force One's flight computer by hacking the terminal on the Hoover Dam visitor center and updating the flight control. The Vertibird will crash soon after it takes off.
Fire the anti-aircraft gun at Bear Force One as it is coming in for its landing. This is done by using the console (which requires a Science of 50) that is atop the exterior staircase due east of the visitor center. The console is next to a ham radio.
Rig the anti-aircraft gun to explode by using the console (described above), but use a Repair check of 50 instead of Science.
Plant a charge of plastic explosives to Bear Force One after getting past Private Jensen by either sneaking past, persuading him with a Speech check of 55, or dressing as an NCR engineer (there is an NCR engineer in the visitor center who can be killed and his jumpsuit taken). The charge will explode when Bear Force One takes off.
Plant a charge of plastic explosives in Private Jeremy Watson's helmet, which is on the table next to the stairs below the visitor center. Watson (who lost his helmet) can them be pointed in that direction. When he approaches President Kimball to accept his honor, Kimball is within range of the charge for it to be detonated.
If all else fails, one can attempt to destroy Bear Force One through conventional mean, although the Vertibird has a high damage threshold and number of hit points.
Drawing a weapon while near the visitor center and after the president has arrived will result in the President and NCR reacting as if he had come under attack, even if the Courier is hidden and has not attacked. However the NCR will not turn hostile unless they see through the Courier's disguise.
PlayStation 3Xbox 360 Cato can spawn very close to the cazador nest, putting him in danger of death from the moment the quest begins. To avoid this, fast-travel to the area before taking the quest, clear out all the cazadores, and then go to the Fort to receive the quest.
PlayStation 3Xbox 360 If the player visits the Dam after receiving the quest but before making contact with Cato, the quest will automatically fail when he leaves the Dam area. If the player waits at the Dam without having met Cato, the President will never appear.
PlayStation 3Xbox 360 Sometimes the quest will outright fail when started forcing you to report failure to Caesar.
Xbox 360 If the player kills the President at close range, the system will most likely overload and freeze up because of all the activity of the crowd and troops.