Comment by chrisseaton

It's covered in the Bakula movie - they stripped the plane down to the extreme and installed fuel tanks so huge that they could barely take off.

That's also why he was on his own - his oppo crashed on takeoff due to the massive fuel load.

It looks like the full movie with the explanation is on YouTube https://www.youtube.com/watch?v=-4_f3T8AzJo.