[nradov]

You've got to be kidding. The civil aviation authorities would never allow airlines to jettison solid objects over populated areas for safety reasons.

[J-dawg]

What if the jettisoned objects were autonomous aircraft that could land accurately at a specified location?

[srssays]

A better idea would be to dig oil out of the ground, process it into kerosene, and use that to power jet turbines on the aircraft.

[J-dawg]

At some point we're going to need to stop doing that, hence the need for alternative ideas.

[nradov]

If the goal is to reduce carbon emissions from aviation then a more viable approach would be to produce liquid hydrocarbon fuel as a biofuel or through artificial synthesis using electrical power from renewable sources. Barring a technology breakthrough, batteries will only be usable for the shortest flights.

[srssays]

Sure. How about LNG (liquid methane)? We have enough natural gas to last quite a while. In the far future, hopefully we will have mastered producing kerosene using algae.

[tankenmate]

LNG tanks are far from lightweight; to keep LNG at room temperature is about 320 atmospheres of pressure. Liquid propane on the other hand is about 8 atmospheres. Mind you at altitude it's around -50 ~ -60 C, but that will only reduce the pressure requirements to approx 100 atm. Also, LNG has about 60% of the energy density of kerosene. SO to use LNG you'd be taking a double whammy, lower density and heavier tanks.

[srssays]

Sounds like propane is a winner. Would it help to use a composite tank a la SpaceX?