Just saw on tv ALL national parks are free admission today. I dont know how many you can fly to, I know the Grand Canyon is one with airport next door, maybe you can fly right into Kitty Hawk which I think is national and should be. I have flown to visit Yellowstone and Yosemite (great) and recall some driving from the airport not sure how much. Wouldnt it be great if most parks had a runway right at the entrance? And I know this info may not help much if you didnt know it before but I just now saw it. If one is going, most places are likely to have good weather this time of year.