In Air Tycoon Online Series, players conduct Guerrilla warfare, originally a form of irregular warfare in which a small group of combatants such as paramilitary personnel, armed civilians, or irregulars use military tactics including ambushes, sabotage, raids, petty warfare, hit-and-run tactics, and mobility to fight a larger and less-mobile traditional military, against "enemies" by putting (multiple) planes in their routes and set airfares to 0.4, in order to force the enemy to reduce airfares or close the route. I ([[User: Admiral Alvin}}) has tried this on one of the top 3 airline and successfully made its company value to decline by 98,000,000K with the help of economic crises. However, normally that doesn't happen unless multiple airlines attack your routes together.
Cargo routes are much easier to attack. Cargo routes take, potentially, months to achieve full occupancy. After you forced your enemy to close a route, he will take months to re-establish a route with full occupancy and guess what? His new routes are gonna be attacked again.