Totally unfeasible.
The next WTC will be done by inserting sleeper agents into the Professional Pilot Community.
This time they trained their agents right through to the type rating courses.
Next time - possibly already - they will simply wait until their agents get legitimate jobs in airlines. It would not be difficutly - they could easily afford it.
Which makes all this malarky rather redundant.
Not to mention the simpler technique of just sitting in Hounslow on the approach to 27 with a few stingers and turning all three aircraft on final into gliders with the obvious consequences...
Intelligence and appropriate security service actions are the only solution.
WWW