It's hard to say definitively which is "worse" for the environment, smoking or flying, as they have different impacts on different aspects of the environment. Here's a breakdown:

Smoking:

* Direct impact: Primarily contributes to air pollution through particulate matter, carbon monoxide, and other harmful chemicals.

* Indirect impact: Contributes to deforestation due to tobacco farming, and has health impacts on smokers and those exposed to secondhand smoke, leading to healthcare costs.

* Overall: Smoking has a significant impact on local air quality and human health, but its global impact is less than flying.

Flying:

* Direct impact: Major contributor to greenhouse gas emissions, particularly CO2, contributing significantly to climate change. It also releases other pollutants like nitrogen oxides and soot into the atmosphere.

* Indirect impact: Fuel production and infrastructure associated with flying also contribute to emissions and environmental damage.

* Overall: Flying has a much larger impact on global climate change due to its significant contribution to greenhouse gas emissions.

Conclusion:

* For local air quality and human health: Smoking is worse.

* For global climate change: Flying is worse.

However, it's important to consider:

* Frequency: A person who flies occasionally might have a smaller overall impact than a heavy smoker.

* Alternatives: There are alternatives to smoking, such as vaping or quitting entirely. However, there are few viable alternatives to flying for long distances.

* Efficiency: The environmental impact of flying can be reduced by choosing fuel-efficient aircraft, flying direct routes, and offsetting emissions.

Therefore, it's more accurate to say that both smoking and flying are harmful to the environment, and efforts should be made to reduce both activities where possible.