I'm not sure that the entire concept is ridiculous, but would have certainly want to witness it in action to see if there is any meaningful effect. I've seen plenty of fires where the helicopter and fixed wing resources were pretty ineffective and almost irrelevant (to say the least) against massive fire complexes, where they could only offer limited resistance to an overwhelming onslaught of fire. We've all also seen plenty of times when there is no flying due to smoke, wind or other factors.
Twenty years ago, everyone laughed at the concept of fixed wing jets in the fire-fighting market and just look where we are today. Fire-fighting resources require a complete toolbox of tricks and resources, and I'm not sure that this one is without potential merit. It's been the staple resource of the oilfield firefighting business for decades.
Scientists test explosion method that could see wildfires stopped in their tracks | Daily Mail Online