The U.S. Forest Service says it is adding four aircraft to its firefighting fleet as California recovers from a spate of blazes and other fire-prone states brace for another hot, dry summer. In a statement, the service said it will have a second DC10, which can carry up to 11,600 gallons of retardant, and three smaller planes that can carry up to 3,000 gallons. That brings the total to 21 large airtankers and more than 100 helicopters. The announcement comes as the Obama administration pushes Congress to ensure that enough money is available to fight destructive wildfires. The Forest Service expects to exceed this year’s budget in July, two months before this fiscal year ends.