Going reveals the most affordable national parks to fly to, with Indiana Dunes National Park topping the list at just $138 round-trip from nearby airports. Close to Chicago, it offers dunes, beaches, hiking, and diverse wildlife. Other budget-friendly parks include White Sands, Big Bend, and the Grand Canyon. With travel costs rising for popular parks like Yellowstone, these accessible destinations offer great summer options—just remember to respect park guidelines amid reduced staffing.