[Johnny555]

A $30,000 car that lasts for 200,000 miles costs you $0.15/mile or $450 one way for 3000 miles (I ignored age-based depreciation, but also didn't account for other costs like maintenance and insurance). At 30 mpg (because a car that a family of 6 can feel comfortable riding/sleeping in for 40 hours is not going to be a compact car), that's around $250 for gas.

So you're at $700, or $1400 both ways.

With advanced purchase, you can get flights from SFO to NYC for $250, so that's $1500 for your family of 6.

I find it hard to get good sleep in a car, I can't imagine having a good experience trying to sleep 4 nights in a row. Nor can I imagine spending 40+ hours in the car over 4 days with the kids, even if they are sleeping a lot of that time.

[aidenn0]

Using similar calculations, we figured it at about $2k for our roadtrip last summer, so sounds right.

However, flying:

$550 after taxes and fees is the cheapest I've gotten an LAX/IAD roundtrip for in a while, so $3300 minimum for flying.

Parking for 3 weeks is about $200

$3500 is the flying price, and often I can't get tickets for under $600 that match our schedule.

Depending on the 405, it can take 3 hours to reach LAX and park. You really don't want to have to be running through the airport with little ones, so plan to be there 90 minutes before flight. It usually only 4 hours in the air going west-to-east (east-to-west is longer) but figure time sitting at the gate an taxiing means a minimum of 5 hours on the airplane. So nearly 10 hours of travel time.

Issues with flying that were non-issue in car:

We cannot change our schedule even by a few hours without incurring fees with the airline.

LAX/IAD, plus price sensitivity means almost certainly flying United. I'm not paying the economy plus price times six, so my knees are touching the seat in front of me the entire time.

We had a 20 month old, already nervous from flying for the first time fall asleep on the taxi-way with her seatbelt on, resting her head on my wife's lap. The flight attendent insisted she must be sitting up for takeoff. Said child was screaming for the next 90 minutes from being woken up.

kid potty training? Not while flying, since the fasten seatbelt sign always goes on at the most inopportune times.

It's true that none of these were enough to get us to stop flying (having a kid with PTSD was what did that; you don't want to be locked in a box with 200 strangers when he gets triggered), but it was surprising how much less stressful it was even compared to flying before we had him.

Perhaps cross-country will still be niche, but certainly day-long road trips will jump in popularity when nobody has to do the driving.

[greedo]

You also need to calculate the cost for a rental car at your destination when flying. So add roughly $100/day to your total stay. When driving, you save that right away.

[Johnny555]

This whole discussion is about how self-driving cars will make car ownership unnecessary -- you don't need a rental car at your destination, you just call a cheap self-driving car to drive you around just like you do at home.

[greedo]

The parent was comparing flying to driving cross country.

[Johnny555]

He's comparing riding in a fully autonomous self-driving car that will let him and his family sleep at night when he's driving to flying. He's not planning on driving his car 40 hours over 4 days himself, I think the number of people that consider that to be a viable option over flying are very low indeed. I can almost agree with him that a self-driving car would make this viable, but I think he's overestimating how comfortable 4 nights of sleeping in the car on the road will be for him and his children.

When that fully autonomous self-driving car exists, then cheap self-driving cars for car-share will exist.