Special rules are often incorporated into airsoft games in order to make basic games more interesting or to increase "longevity" with seasoned players.
These may include Medic rules and rules regarding hits to one's equipment, artillery units with bazookas, mortars, grenades, and many more mods.
Air strikes at s.w.a.t. have been used in the past to stir up stale games, this also is worked well in situations were role play from the marshals acting as downed pilots and drug lords in the past.
sometimes vehicles are used as transport to carry troops to a remote part of the game area: