biofuel

On the other hand, it would make sense to grow this biofuel only in places where the environment is optimal for the most aggressively ethanol-producing plants.

That's not cheap, but it's a damned sight better than pretty much any biofuel alternative, which runs about $1000/bbl.

Also, don't support biofuels and speak out against them and especially subsidies that favor biofuel production.

Your primary alternatives are sail power, biofuel (including possibly pelletized wood ships, an existing proposal), or electrically-generated synfuels as here.

If you're powering jet planes, you're going to need some type of biofuel, which is very inefficient per unit area.

It doesn't help that many countries now have a mandatory biofuel component.

Again, we grow more corn for biofuel than we do for livestock because of government subsidies.

That said, maybe biofuel (algae?) can replace fossil fuels for aircraft.

It would also serve as a great investment for biofuel transportation.

However, many important environmental effects of biofuel production are poorly understood.

Ocean freight is almost certainly more affordable, and does have fuel flexibility aircraft don't have: both wind and solid biofuels (particularly pelletized biofuel) are possible.

Is not amazon deforested to make place for biofuel plantations?

Biofuel are actually a reasonable long term solution to the flight problem.