The short answer
Driving costs are mostly paid per car. Fuel, tolls and parking cost the same whether one person or five are inside. Flying costs are mostly paid per person: every traveller needs a seat and usually a bag. So the more people share a car, the more likely driving wins. The further you go, the more fuel, hotel nights and time push the answer towards flying.
To compare your own numbers, use the driving vs flying calculator. It also shows the group size at which driving becomes cheaper.
What to count on each side
Driving
- Fuel for the full distance, there and back. Our fuel cost calculator works it out in US, UK, Canadian or Australian units.
- Tolls, and parking at your destination.
- Overnight stops if the drive is too long for one day, plus meals on the road.
- Wear and tear: tyres, servicing and depreciation. It's easy to forget, but it adds up on long trips.
Flying
- Fares for every traveller, return.
- Bag fees and seat selection. Budget fares often leave these out.
- Getting to and from the airport: parking, a taxi or a train at both ends.
- Transport at the destination, such as car hire or taxis, if you would otherwise have had your own car.
fly = (fare + bags) × travellers + airport costs + destination transport
Worked example 1: one person, 400 miles each way
A solo traveller drives 800 miles round trip in a 30 mpg car with gas at $3.50 a gallon. Fuel is 800 ÷ 30 × 3.50 = $93.33, with no tolls. Flying costs a $180 return fare, a $35 bag fee, $30 airport parking and $60 of taxis at the other end: $305.
On money alone, driving saves about $212. But it takes around 14 hours behind the wheel against roughly 6 hours door to door by air. If that traveller values their time at $30 an hour, driving costs 93.33 + 14 × 30 = $513.33 and flying costs 305 + 6 × 30 = $485. Flying now comes out $28.33 cheaper. On trips this close, the value you put on your time decides the answer.
Worked example 2: a family of four, 900 miles each way
Driving 1,800 miles round trip at 25 mpg and $3.50 a gallon uses $252 of fuel. Add two motel nights at $130 ($260) and $120 of extra food on the road: $632 in total.
Flying the same family costs $280 per fare and $35 per bag for four people ($1,260), plus $60 airport parking and $300 for a rental car at the destination: $1,620. Driving saves nearly $1,000. This is the typical pattern for families and groups.
Worked example 3: finding the break-even point
Take a car trip where driving costs $160 in total and flights are $100 per person with no other costs. One traveller: driving $160, flying $100, so flying wins. Two travellers: driving is still $160, flying is $200, so driving wins. The break-even group size is 2. The calculator does this search for you, for groups of up to 12, assuming everyone fits in one car.
Other things that tip the balance
- Luggage and gear: skis, bikes or a lot of baggage make flying more expensive and more awkward.
- Pets are usually easier and cheaper to take by car.
- Flexibility: a car lets you stop on the way and leave when you like. Flights don't.
- Fatigue and safety: very long drives in one day are tiring. Build in rest stops or a night on the road.
- Price changes: fares can rise as the date gets closer. Fuel prices change too. Use the prices you can actually get today.