I flew on demand 135 in the past and this fuel thing will be hitting that flying pretty hard as well. I hated 135...I'd be up at about 0400 getting donuts and newspapers for the passengers, fly for a few hours and then sit all day at an airport waiting... an hour before scheduled departure..customer would call, where gonna have dinner with our clients and will be a few hours late! Part 121....pax is late...see ya catch the next flight!!