Like many major events in history (including most wars and revolutions), it's probably best interpreted as the product of both large-scale and systematic factor

Like many major events in history (including most wars and revolutions), it's probably best interpreted as the product of both large-scale and systematic factors as well as happenstance and small-scale interventions -- like the timing (and relative speediness, compared to a boat) of this particular chartered flight. To refer to an even larger-scale example: clearly the Russian Empire was in the throes of an extended period of turmoil and conflict in the last years of the House of Romanov, which by that point was unlikely to stay in power for very long in any case... but at the same time things might very well not have turned out quite the way they did had not the German government approved that famous train ride from Zürich to Petrograd for Lenin and his entourage in February of 1917 (as nifty way, so they thought, of seeding just the right amount of chaos to induce in the Empire to soften its resolve to continue the fight against the Central Powers).