I know; why not build a 10ft high and 10ft thick concrete wall all around the perimeter, and rename the airport Stalag Elmdon?
Avman - extremely good point. We live in a world of 20/20 hindsight, running parallel with the UK mantra "Security is Paramount".
We also allegedly live in a free country, and one of the pay-offs of living in such a "free" environment, is that security such as you have tongue in cheek suggested is just unacceptable. Anyway, if such a defence was errected then the eejits who attached the WMP helicopter would just have found any less well protected target to go after.