There seems to be a some common threads in a lot of the repsonses that I want to address.
1) The comments regarding selectively choosing parameters to create a desired outcome in the examples. In fact, everyone here is doing it. I'd say the only parameter that I disregarded in all my flying calculations that I probably should have included if I was trying to create a 'common' scenario was rental car, especially if you are going to WDW. I'd say it is more common to leave it out for
Disneyland.
But the converse is that most everyone here who did their calculation also did it with selective parameters too, namely leaving out depreciation, cost of lost time/opportunity, and the increased risk of driving long distances. While on the depreciation, I agree if you are driving a car with 80,000-120,000 miles on it, it becomes insignificant, but then I'd say the vast minority of drivers not only on this board but also to Disneyland are driving newer cars with much less than 80,000 miles. Just because the used car value websites don't change the value when you add another 1,000 or 2,000 miles doesn't mean it is not a factor. The way the web sites work is the price goes down when you go past certain points, usually in 5,000 increments. So if you put 39,000 then 41,000 you may see the value drop but 37,000 then 39,000 nothing happens because 40,000 is the cut-off. If you recorded every signficant trip of 100 miles or more you made in your car, then wanted to evaluate how much each trip affected your car value, it would never affect it if you checked it that way as 100 or 200 miles or even 800 miles won't make a difference on those web calculators. 40,000 miles will. That is typically the point where most cars are worth cloe to half what they were brand new. So on a $30K car, at 40,000 miles, it has a trade in value of $15K. That's an average depreciation of $0.375 per mile. The trips you took to Disney when the car was pretty new would depreciate it more than that, the later trips less than that.
When I first started this thread I had no expectation for anyone to count the cost of lost time/opportunity. It something more common in the investment world. And I don't expect to convince anyone that their free time has a monetary value (but it does.)
One poster valued their time at $60,000 - granted it was a joke, but they get my point. I valued mine at $1,100 for 28 hours extra spent in a car instead of watching sports from the comfort of my couch (just kidding, I'm not that into watching sports.) And on my own estimate, I did count ALL the time for flying including driving to/from the airport and arriving 1.5 hours before the flight.
So I view disregarding the lost opportunity cost just as "selective" as leaving out rental car cost. The thing is, the rental car is technically not a *required* cost. The lost time spent in the car all those hours - you can't get around it (unless you have a time machine), aside from saying you don't mind so saving all those hours isn't worth anything to you. You can say the driving is a "fun" and memorable part of the trip, I don't disagree, it can be. But I do contend there are other even more fun and memorable things you could be doing those 20+ hours. Everyone is entitled to their opinion, especially about the value of their free time and how they like to spend it. I just think if you took a poll across a good representative group of people, sitting in a car will not be high on the list.
One poster pointed out they do not gain much in the way of extra days if they fly. Extra days on the vacation are not the lost opportunity here. No matter how you cut it, driving takes a lot longer as far as the number of hours spent traveling provided you are a significant distance from the park. As many posters here have pointed out, they couldn't afford to spend the extra days at Disney anyway.
One way to look at it is think of your favorite activity that doesn't cost any money. I can definitely say for the majority of people it is NOT sitting in a car. Maybe playing baseball with your kids is it, or playing some sport yourself. Or working in your garden. Or hanging out at the beach. Something you really like to do but never seem to have as much time as you would like to do it as much as you like. Then think for a small fee (cost of lost opportunity is only a part of the total cost of driving) you can spend all those hours doing other activities that you like better instead of sitting in a car.
The cost of lost time/opportunity can be illustrated in a lot of different scenarios. I would bet in some scenaros, people WOULD put a value on the saved time/inconvenience and opt for the more expensive option given a choice. They just select not to do it in this case for whatever reason. It is sort of like standing at a Ferry dock. There are two boats going to the same place. Boat A takes a shortcut that takes only 2 hours and is on smooth seas. It costs $40/person for a ticket. Boat B takes a long rough route and makes some stops on the way and takes 12 hours to get there and you most likely will get seasick. The ticket is $20/person. Some people will stick it out just to save the $20 no matter how much time and inconvenience is involved. That's their perogative. Some people simply don't have the $40 but my contention is if something is important enough they always find a way to afford it. Here the difference in money is small compared to driving/flying to Disney. But technically, you are putting a value of $20/ 12-2 = 10 hours = $2/hr on your free time. Not very much, but more than anyone here has placed on it except myself and the $60K person.
So I'll include rental car cost in my estimate when you include lost cost of opportunity.
2) Regarding the total trip cost having a bearing on the descision to drive or fly - someone said it was not relevant. I disagree. It goes back to the mindset of saving a buck no matter what. A buck saved is a buck saved. Well the saying "a penny wise, a pound foolish" comes into play. My analogy would be buying a new car. The new car costs $30K. The Air Conditioning option is $400 extra. In order to *save* $400, you opt not to get the air conditioning even though you live in an area that gets hot for several months out of the year and $400 represents only 1.4% of the total cost. While most of the scenarios posted here, people are saving at least 20%. My point is the more typical scenario you won't save that much as a percentage of the entire trip. So the savings becomes less significant.
Are there families that take a week vacation to WDW where they splurge once they get there and stay in a decent hotel, eat out in decent restaurants, hit some water parks or see some shows, and buy some souvenirs? Definitely. And do some of those families drive to save money? Definitely. I just find it a little odd that someone would spend $4K+ on a trip and then spend 20+ hours extra in a car, putting their family at 65 times the risk to save a relatively small percentage of the overall cost. Granted no one here has indicated they are in this group as most people that drive are on a tight budget to begin with. But I think this other scenario may be more common than you would belive. I'm talking about scenarious inbetween the extremes posted here. Doesn't look like anyone here falls in that category, but to be honest the trip in most cases ends up costing you more than you think it would, not much more if you are well disciplined. I'd say most people don't even count up all the receipts when everthing is said and done, so most don't even know the grand total. They just pay as much as they can on the credit card bill and live with it. All they know is they save some amount of money driving.
2) Safety - Driving is 65 times more dangerous than flying. One poster pointed out they *feel* more safe being in control of the vehicle. You and millions of others feel the same way. But feeling safe doesn't make you any more safer. In fact feeling *unsafe* will make you drive slower. I've driven short distances when I was tired, and felt stupid for doing it, but I was less tired than I would be at the end of 10, 12, 15 hours of driving without sleep. I'm not going to give a lesson in statistics here but the fact of the matter is every additional mile you drive, you are a little more likely to be in an accident. There is a value associated with not having to drive an extra few thousand miles. That's why when you apply for auto insurance they ask how many miles a year you drive. The more you drive the more likely you are to get in an accident. That's just the fact. The fact also is the posts here do not accurately represent all the drivers out there. Someone who got in a bad wreck and injured their children on the way to Disney is NOT likely to be posting their story here in this discussion - they're not even on this board. As the saying in the investment world goes "past performance is not an indicator of future performance" - Just because you haven't gotten in a mishap thus far, doesn't preclude you from getting in one in the future. Statistically something will probably eventually happen if you drive enough miles over the years, especially if you do it for many hours at a time without rest. Lets just hope it is minor. Some call this paranoid, I call it being intelligent about recognizing actual risk factors and mitigating them reasonable to do so. This aspect hasn't been discussed in depth that much compared to the other issues because the facts are the facts. What is subjective about it is how fast you drive, how long you drive without rest, and the condition of your car. I still contend, and I'm not alone on this, that driving for many hours without sleep increases the risk and is not a wise decision (especially if your children are in the car) and I don't see how anyone could debate otherwise. Don't talk to me though - plead your case to any safety expert, any state patrol officer, any parent who fell asleep at the wheel or spaced out and drifted off the road -- Mrs. Pete defintely should talk to one of these people based on her previous comments. None of those people who had an accident actually thought it was going to happen to them. They probably pulled it off (driving straight through) numerous times before. If they thought it would happen to them, they wouldn't have been driving that long in the first place. Maybe you will pull it off an in your half dozen or more trips and 12,000 plus miles on the road to Disney not having one hitch. Lucky you.
3) Airfares can change more rapidly than gas prices. Your more likely to save $100's on airfare if you are patient and plan in advance, study the 90-day history and buy your airfare when it is at a low point. That's when the gap between driving and flying really closes. If you happen to evaluate the costs when airfares happen to be high, especially if you have a family larger than 4, then it isn't surprising that driving is cheper All the scenarios here appear to involve airfare that was NOT a low point. But everyone can't always wait and wait and there is no guarantee it will come down.
It appears most the people who have posted made the right decision for their circumstances. (As I said before, people are NOT likely to post about a bad decision made anyway - they are more like to post to defend their decision.) The point is at least people here are even analyzing the costs at all (aside from the safety factor and cost of lost time which are as someone pointed out very subjective - but factors nevertheless.)
A bid you a safe and fun trip whether you are driving or flying!
So let's have the wear & tear/depreciation cost each way to $190.
, but I don't understand why you're starting to factor in the cost of tickets, rooms, and meals once you arrive? What's that got to do with cost of driving vs flying? I would understand it if we were talking about an overall vacation budget, but that wasn't your original debate.
Another $20 (I rounded this figure up). Total so far is now at $323. On the way home, we hit a CiCi's for dinner. I want to say that was about $25. Stopped for the night- another $100. Hotel offerings for breakfast were awful, hit Mc D's for another $20. Lunch at an Arby's another $20. So the drive down and back cost us $488. Compared to the lowest airfare I could find, plus adding in another $150 more to what we spent on the car rental in October (because I won't do another trip w/o a car), we saved $1166 by driving. That's a substantial amount of money to me.
), go to bed.
He's an experienced, safe driver who knows when enough is enough and isn't afraid to pull over for a nap, or just call it quits for teh night and get a hotel room. Because he drives an ambulance, he's required to take ongoing training in how to avoid accidents. Is that foolproof? nope, but it certainly gives him the edge. And unlike Consultant, he doesn't go roaring along getting $120 speeding tickets. 
