It is true, that the chance of being the victim of a terrorist attack is very low (especially on the plane), but there is a problem:

IF terrorists are already ON the plane and their plan is to take it down, the death rate (if the attack is successful) will likely be 100%, because there is no way out of the plane that is crashing from 30,000 feet. Average plane can carry 200-300 people.

Now let's look at history examples of the situation you are describing:

1. 2002 Los Angeles International Airport shooting
   • Weapon: Glock 21
   • Victims number: 90 people in the line
   • Outcome: 3 deaths (including the perpetrator), 5 injured
2. 1974 Los Angeles International Airport bombing
   • Weapon: Bomb
   • Victims: around 50 in the lobby
   • Outcome: 3 deaths, 36 injured
3. 1975 LaGuardia Airport bombing
   • Weapon: Bomb
   • Victims: Unknown
   • Outcome: 11 deaths, 74 injured
4. 2019 Naval Air Station Pensacola shooting
   • Weapon: Glock 45
   • Victims: Unknown
   • Outcome: 4 deaths (including the perpetrator), 8 injured

I could list more examples, but the point is that death rate during terrorist attack in the airport is significantly lower than on the plane, but that .1% you mentioned will always (or at least in most cases) end in hundreds of deaths, and the actual number of dead people (the count by souls) globally will not stay the same with the percentage rate (still that 0.1%) when the number of planes in the air increases year by year. What I am trying to say, is that we MUST improve security in airports to keep the number of dead souls on the same level. And yes, it will include x-ray (which btw will not have a harmful affect on you, because the X-ray machine's run time and radiation is so low that you're more likely to get radiation sickness from your cell phone than from a scan.)