Holiday Travel Carbon Footprint: Air vs Road

Holiday travel can feel like a few “normal” trips — until you zoom out. For year-end holidays alone, American Automobile Association projected 122.4 million travelers in the U.S., with ~89% traveling by car and ~8.0 million by air. That volume is why holiday travel becomes a climate moment: tiny per-trip differences scale into real emissions.

This post breaks down which holiday travel choices create the highest carbon footprint, why, and what “lower-carbon” looks like without turning the holiday into a guilt trip.

Why holiday travel spikes emissions

Holiday travel tends to stack the deck toward higher emissions:

• More total miles (family visits, multi-stop trips, weekend getaways).
• More congestion and idling (especially road travel).
• More short flights (the least efficient kind of flying, per mile).
• Peak-demand strain (airports, traffic, ground transport, and energy use all rise at once).

None of this means “don’t go.” It means your choices matter more than usual — and small shifts can create ripples that grow into waves.

What “carbon footprint” means here

You’ll see comparisons expressed as grams of CO₂-equivalent per passenger-kilometer (gCO₂e/pkm). Two important clarifiers:

1. Per passenger matters
   A car carrying one person is effectively “one seat used.” A car carrying four spreads the same fuel across four people.
2. Flights have extra warming effects at altitude
   Aviation isn’t just CO₂. Contrails and other chemistry at cruising altitude can increase warming impacts. The UK government methodology used by Our World in Data includes these effects in “CO₂e,” using a multiplier of ~1.9 (with uncertainty).

Quick reality check: common travel modes (per person)

Using UK government emissions factors summarized by Our World in Data, typical footprints per passenger-km look roughly like this: petrol car ~170 gCO₂e, national rail ~35 gCO₂e, short-haul flight ~154 gCO₂e, domestic flight ~246 gCO₂e (CO₂e includes non-CO₂ aviation effects).

The headline: rail is usually far lower than both cars and planes, and domestic/short flights are often the highest per-km.

The highest-carbon air travel choices (and why)

Flying is where holiday footprints can jump fast — not because everyone flies, but because some flight patterns are especially emissions-heavy per person.

1) Short flights and “connecting” itineraries

Short flights burn a lot of fuel in takeoff/climb relative to total distance, so per-mile emissions are higher than longer flights.
Connections also add extra takeoffs/landings and often detours.

Practical takeaway: If you must fly, prioritize nonstop when possible.

2) Premium cabins (business/first) dramatically raise per-person emissions

Why? You’re effectively “claiming” more space/weight per passenger, so emissions get allocated more heavily to that seat.

UK conversion factors illustrate the scale (long-haul, per passenger-km, excluding radiative-forcing uplift):

• Economy ~70.9 gCO₂/pkm
• Business ~205.5 gCO₂/pkm
• First ~282.9 gCO₂/pkm

That’s roughly ~3–4× the footprint per person moving from economy to business/first, before adding the non-CO₂ uplift discussion.

Practical takeaway: Economy is usually the “least-bad” seat choice for emissions.

3) The non-CO₂ factor (contrails, NOx, etc.) adds uncertainty — but it’s real

The UK methodology notes aviation’s non-CO₂ impacts and recommends a 1.9 multiplier as a central estimate (with significant uncertainty, and not a perfect instrument).

Practical takeaway: Even when CO₂ looks “comparable,” aviation can carry extra warming impact.

The highest-carbon road travel choices (and why)

Road trips dominate holiday travel volume in the U.S. (again: ~89% by car in AAA’s year-end holiday forecast). That doesn’t mean road is always worse than flying — it means small improvements can scale massively.

1) Driving solo (one person per vehicle)

A typical passenger vehicle emits about ~400 grams CO₂ per mile on average, and EPA notes this varies mainly with fuel economy and fuel carbon content.
If you’re alone, you carry the whole footprint. If you carpool, you split it.

Practical takeaway: Carpooling is one of the biggest “no-tech” wins.

2) Bigger, less fuel-efficient vehicles

EPA’s per-mile figure is an average; vehicles with worse fuel economy emit more per mile.
Holiday travel often involves loaded cars, roof boxes, or towing — all of which can push fuel use higher.

Practical takeaway: Right-size the vehicle (or at least avoid empty roof racks/boxes).

3) Congestion + idling

Stop-and-go traffic and idling add emissions without adding miles. Holiday travel amplifies this effect.

Practical takeaway: Off-peak timing matters.

“Air vs road” isn’t the full story: distance changes the answer

A key nuance from the same dataset: for very long trips, flying’s per-km footprint can be closer to (or sometimes lower than) driving alone over the same distance — because long-distance highway driving adds up, and long-haul flights are more efficient per km than short ones.

But:

• If you’re choosing between a short flight and a train: train wins by a lot.
• If you can fill the car (2–4 people), road can beat flying for many trips.

What to do instead: a holiday travel plan with less climate damage

This isn’t about perfection. It’s about changing the default settings.

Lower-carbon decision stack

1. Can you shorten the trip?
   Closer destinations reduce emissions no matter how you travel.
2. Can you switch modes?
   If rail is available, it’s often one of the biggest cuts (rail ~35 gCO₂e/pkm vs car ~170 and domestic flight ~246 in the OWID comparison).
3. If you drive: fill seats
   Even one extra passenger can meaningfully reduce per-person footprint.
4. If you fly: reduce the multipliers you control

• Choose nonstop
• Choose economy
• Pack lighter when feasible
• Avoid last-minute “multi-flight” routing if you have alternatives

5. Make the “extra” part of travel circular
   Holiday travel comes with stuff: single-use snacks, bottled drinks, new outfits, cheap gear. If you cut waste here, you cut upstream emissions too — and keep the trip from creating a second footprint at home.

What’s changed

Two things have shifted in recent years:

• Aviation accounting is more honest about non-CO₂ effects. Methodologies increasingly reflect the reality that warming impact isn’t just CO₂.
• The biggest wins are behavioral, not “recycling.” For travel, the high-impact levers are: distance, mode, occupancy, routing, and seat class.

FAQs

What holiday travel has the highest carbon footprint?

High-footprint patterns include short flights, connecting itineraries, and premium cabins (business/first), plus solo driving in a less fuel-efficient vehicle.

Is flying always worse than driving?

Not always. For very long distances, flying can be comparable to (or sometimes lower than) driving alone per kilometer — but domestic/short flights are often high per km, and rail is usually far lower when available.

Why do domestic flights show a bigger footprint per kilometer?

Short flights spend a larger share of fuel in takeoff/climb, which is energy-intensive, so per-km intensity rises.

Does seat class really change emissions that much?

Yes. UK emissions factors allocate higher per-passenger emissions to premium cabins; long-haul business and first can be multiples of economy per km.

What’s the simplest way to cut road-trip emissions?

Carpool. You’re spreading the same vehicle emissions across more people. EPA’s average per-mile emissions make occupancy one of the biggest practical levers.

Final Thoughts

Holiday travel is a mirror: it shows what we value — connection, tradition, presence. The goal isn’t to make people travel less out of shame. It’s to travel with intention, so the memory isn’t powered by avoidable waste and avoidable emissions.