I agree with this only to a point. Banning flights can stop any access disabled persons may have to see national park areas. The other issue that can be a problem is funding. Remember national parks charge admission since the 1990’s to get additional funds, just like a lot of other formerly “free” government services. Banning visitors or other transportation methods keeping visitors out will reduce this funding. Out of sight, out of mind. Your average taxpayer is going to be less willing to pay taxes for something that the taxpayer can’t see or directly benefit from.