Nah. The most likely scenarios are a switch to pure ammonia combustion and/or sourcing "all green" methane to make carbon-neutral or near-zero emissions flight

Nah. The most likely scenarios are a switch to pure ammonia combustion and/or sourcing "all green" methane to make carbon-neutral or near-zero emissions flight. Unfortunately, ammonia combustion is inefficient and synthetic hydrocarbon fuel is far too expensive atm. We'll never get away from the brutal physics: 1. Long flights require planes to get lighter (burn fuel) as they go further so battery power doesn't work. 2. Wings are just too damn efficient at producing lift. 3. Putting enough on-board safe-station-keeping power (weight) on an airship makes it a very poor airship. 4. A very good airship is least safe to fly precisely where is has the most potential to cause damage and loss of life.