What are the realistic alternatives to flying?

Rail, coach, ferry and — for some journeys — simply not going, and the honest position is that alternatives are excellent for some routes and genuinely impractical for others, with the deciding factors being distance, time available and cost.

Rail. Competitive on journeys up to around four to six hours, where centre-to-centre travel removes airport transfer, check-in and security. Rail carries a small fraction of aviation's emissions per passenger kilometre on electrified lines. Where it fails: cost, which is frequently higher than a budget flight and is the single largest barrier; fragmented booking across operators, which makes international journeys unnecessarily difficult; and reduced overnight services in some regions, though sleeper routes have been reintroduced in several countries.

Coach. The cheapest option and frequently the lowest emissions per passenger when full. Slow, and genuinely viable for those with time and limited budget.

Ferry. Essential for island connections and pleasant on some routes. Emissions vary enormously — a fast ferry can be worse than flying, while a conventional vessel carrying freight as well is much better, and cabin-based cruise ferries are higher again.

Not travelling. Remote alternatives have genuinely displaced some business flying, which is the largest single change in aviation demand in recent years.

How to decide honestly: compare door to door rather than gate to gate, which frequently changes the answer for short-haul; count the time you can actually use, since rail time is usable and flying time largely is not; and include airport transfer costs in the comparison.

Where there is no realistic alternative: long-haul, and intercontinental journeys where sea travel is measured in weeks. Pretending otherwise helps nobody, and the useful framing is fewer and longer trips rather than none.

What actually reduces impact if you do fly: flying economy, since premium cabins occupy far more space per passenger and carry proportionally higher emissions; direct flights, since take-off and climb dominate fuel use; travelling light; and — with substantial caveats about quality — offsetting, which is widely criticised and is not a substitute for flying less.