Calling it an illusion implies that air travel is not safe, when in fact it is very safe. However, people did not feel safe, so the government constructed an agency (perhaps deliberately, perhaps not) to provide security theater and help people feel safe.
In general, American citizens today are safe from terrorism. If anything, the greatest danger comes not from terrorists themselves but from the American peoples' unjustified fear of terrorism. We could use some more security theater.
The ostensible reason that the government has created the TSA and its ilk is for actual security. Claiming that it's been created to intentionally achieve security theater is quite a extraordinary claim to be making. Furthermore, the origin of danger does not come along a single axis running between "terrorism" and "people's fear of terrorism". The government programs themselves can have negative impacts (c.f. any discussion on the TSA, NSA, border controls), which you are conveniently ignoring.
In retrospect, I should have mentioned that last bit instead as a tangible benefit, but I only just now thought of it.
Defensive gun use is far more common in the USA than murders by firearms:
http://guncite.com/gun_control_gcdguse.html
> when we look at the data, all of these provide no tangible benefit, and often great harm.
No tangible benefit? Even 100,000 people saved by guns annually (the low end number) is "tangible benefit".
According to the CDC, there are 11k homicides by firearms: http://www.cdc.gov/nchs/fastats/homicide.htm
If you look at other countries, when guns are banned there is a shift from guns to other methods of killing ,but not a significant decline in homicides.
This is what you see when looking at the data.
It's certainly a perfect example that people see what they want to see, even when presented with overwhelming evidence to the contrary.
I'm talking about you, by the way.