How many people are actually dying from air travel radiation? The numbers are low enough that they’re hard to find evidence for. Here’s a study, for example, that attempted to answer the question for pilots, who obviously fly frequently. They weren’t even able to detect higher death rates at all. https://pubmed.ncbi.nlm.nih.gov/14648170/ “Neither external and internal comparisons nor nested case-control analyses showed any substantially increased risks for cancer mortality due to ionizing radiation.” (Edit: of course there are some studies that demonstrate small amounts of increased cancer risk, and increased risk of pregnancy complications for airline crews. The numbers are small.)
On the other hand, “Tobacco is the leading preventable cause of death in the United States” https://www.cdc.gov/tobacco/data_statistics/fact_sheets/heal...
Even if you are skeptical of the CDC’s estimates for mortality rates by things like second hand smoke, there are pretty clear reasons to take smoking a lot more seriously as a risk than radiation exposure from air travel, the direct risk to smokers is orders of magnitude higher than the risk of air travel radiation.
The fact that the CDC’s language reflects the actual risks is a good reason to put more trust in what they say, not less. They’re not trying to hide something from you, they’re trying to help you understand the actual relative differences in risk, which are much, much higher for smoking.
Edit2: BTW, the WHO agrees with the CDC about there being no safe levels of smoke, and is backed by significant amounts of research and outcome statistics worldwide. https://www.who.int/news-room/fact-sheets/detail/ambient-(ou...