While the IRS may say it's 0.38/mile for your car, there are other ways to look at it.
Assuming someone doesn't purchase a car just to drive to Disney, and the car therefore is necessary whether they drove to Disney or not, then most of the costs for the car are there anyway, even if they flew. The price of the car, payments, insurance, taxes do not go down just because you elect to fly rather than drive to Disney.
So you really can't say it's costing for example $912 to drive to Disney. Even if you flew, you would not realize a $912 savings anywhere for the year. Your only true savings would only be on whatever gas you saved, oil, maintenance, tires etc.
So if you analyze it, for a 2400 mile R/T:
Gas: Average 25mpg at 1.25/gal = $120
Oil: =1/3 of an oil change, or $7.00
Tires:=5% of a 50,000 mile tire, or about $15 if you purchase $75 tires
Maintenance is tough to calculate, especially since warranties are so much better anymore. But if you spend $120/year on tune-ups, drive 12000 miles a year, that's a penny a mile, or another $24.
So total cost to drive the 2400 miles is about $166. That's a far cry from the $912. The big difference is because you will pay all the other fees (cost of purchase, license, taxes, insurance) anyway, whether you drive or not.
Another way to look at it is in used car prices. Dealers give cars a standard mileage when they are traded in. The value of a car is increased if it has fewer than the standard miles, and it is decreased if it has more than the standard miles. So, let's say you would drive the exact standard miles before trading your car in. The dealer offers you a book value. On the other hand, you drove it the 2400 miles over the standard miles. In this case the dealer gives you the book value, minus excess mileage at the rate of 0.07/mile. So effectively they're saying the car is worth $168 less because you drove it to Disney. So even if we add that to our original cost of $166, we only get $334.
The IRS is overly generous. If you purchase a new car every year their 0.38/mile may be closer, but this represents depreciation, taxes, insurance, license fees etc which are extremely high during the first year of ownership. These will all be the same whether you drive 12,000 miles a year, or 14,400 miles a year.