In response to the attacks in Paris, many countries are ready to bomb more ISIS territory even more than they already have. This may work against standing armies, but will it work against a constant recruiting machine that uses the bombing to show how "Islam is under attack."
Put another way: drone bombers create more drone soldiers.
A much better strategy would be dropping leaflets with Koranic verses of charity and forgiveness. Just like some "Christians" select verses from the Bible to justify punitive actions against those that disagree with them, there are "Muslims" who select verses from the Koran to justify their punitive actions. Just like many real Christians select verses from the Bible to lead a life of charity, there are Muslims who select verses from the Koran to lead a life of charity.
What would be the costs of millions of leaflets of Koranic verses of charity versus the costs of hundreds of bombs? Being bopped on the head by a dropped book may change a lot more minds than being bopped on the head by a dropped bomb.