On a "per passenger-kilometer" basis, cruise ships and short-haul flights are the most polluting forms of transport. Cruise ships are particularly high in sulfur and nitrogen oxide emissions due to the "heavy fuel oil" often used in international waters. In the aviation sector, a short flight (under 500 miles) is significantly more carbon-intensive than a long one because takeoff and landing—the most fuel-heavy phases of flight—account for a larger percentage of the total journey. However, in terms of total global volume, road transport (passenger cars and heavy-duty trucks) is the largest contributor to greenhouse gases, accounting for roughly 75% to 85% of all transport-related CO2 emissions. While a private jet is the most polluting choice an individual can make, the sheer ubiquity of internal combustion engine vehicles makes them the primary driver of global transport pollution in 2026, despite the rapid growth and adoption of electric vehicle (EV) technology.