The U.S. Forest Service says it is adding four aircraft to its firefighting fleet as California recovers from a series of blazes, and other states brace for another hot, dry summer.

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.