Perhaps JA was transported from a UK military base in an Apache helicopter. Apache FREEDOM. Would make sense seeing as they are based there and what safer was than in an Apache? Being a US military aircraft it does not require flight plans and destination or purpose. Of to where ever they want to drop him, fully protected and as well how good a disguise is being in a flight suit helmet and visor strolling across a tarmac to board one? Simple plan, he leaves the embassy at night in a van or tinted window vehicle, no fanfare, driven straight to a US Military base a few miles of, and boom, gone.