Your thesis statement should be bold, but also something you can back up with facts throughout the paper. If you say, for example, that airline travel is becoming more dangerous, you will need statistics to prove that. You might want to focus your thesis on the risks vs. benefits of air travel, instead. You could use a thesis statement like "despite the recent disasters occurring in the field of air travel, it remains the safest way for people to get from one place to another." As for structure, you could have an intro, information about the most recent disasters, what causes air disasters (and what's being done to reduce them), and then information about how air travel is still safer than other forms of travel, followed by a conclusion.
