The Gravity of Innovation: Why Your Next Holiday Won't Be on an Electric Jet

The Physics of Flying: Why Jet Fuel still Beats Batteries

If you care about climate change and invest with that in mind, aviation is one of those sectors that can feel frustratingly hard to solve. We all want cleaner flights, and it’s easy to imagine a future where electric planes quietly replace today’s jetliners. But the physics behind flight makes the picture much more complicated.

A lot of people talk about an “electric jet” as if it’s just a matter of time and enough innovation. The truth is that long-haul aviation is a different problem altogether. Jet fuel carries far more energy per kilogram than today’s best lithium-ion batteries — roughly 50 times more. That gap is not a small engineering hurdle. It is the main reason battery-electric aircraft are not close to replacing large commercial planes on long international routes.

The 'Battery Gravity' Trap

In a petrol-powered car, the weight of the fuel is a tiny fraction of the vehicle’s mass.

In a commercial aircraft, weight is everything.

A plane burns fuel as it flies, so it gets lighter over the course of a trip. That makes the rest of the journey more efficient. Batteries don’t work that way. A battery weighs the same at take-off as it does when it lands, whether it’s full or empty.

This creates a circular problem known as "Battery Gravity":

• To fly further, you need more batteries.

• More batteries add more weight.

• More weight requires more lift, which requires more power.

• More power requires... even more batteries.

Current estimates suggest that for a Boeing 787-sized aircraft to fly a long-haul route using today’s battery technology, the batteries would weigh so much the plane wouldn't even be able to lift itself off the tarmac, let alone carry passengers or luggage.

Where Electric Aviation WILL Work First

While an electric flight from Melbourne to London remains a physical impossibility for now, the transition is already happening on a smaller scale. You should expect to see electric aviation emerge in three distinct phases:

1. Short-Hop Regional: Small 9–19 seater planes for 30–60 minute flights (e.g., Sydney to Newcastle). The energy requirement here is low enough that the current battery density is viable.

2. Hybrid-Electric: Similar to a Toyota Prius, these planes use electric motors for takeoff and landing (the most fuel-intensive parts) and traditional engines for cruising.

3. Sustainable Aviation Fuel (SAF):
   This is the likely mid-term winner for long-haul. SAF is made from
   organic waste and can be dropped into existing jet engines, bypassing
   the battery weight problem entirely.

What This Means for Your Ethical Portfolio

When we review ethical investment funds or superannuation options, we look closely at
how "green" claims are justified. If a fund looks to be heavily betting on a breakthrough in long-haul electric aviation without acknowledging these physics constraints, it may be a red flag for "techno-optimism" over realistic ESG screening.

Watch-out: The Greenwashing Gap
Be wary of companies or funds that simplify the aviation transition. A truly ethical investment strategy doesn't just look for the most "futuristic" idea; it looks for the companies solving the SAF infrastructure problem or improving regional electrification today.

Summary: A Realistic Timeline

You could look forward to the next regional weekend getaway in an electric aircraft by the 2030s.

However, your next international holiday will almost certainly rely on liquid fuels—hopefully sustainable ones—for the foreseeable future.

Understanding these limits helps us build portfolios that are grounded in reality, not just wishful thinking.

Next steps

• Review your superannuation’s “Sustainable” or “Ethical” option to see whether it holds aviation stocks and what its decarbonisation case actually is.
  

• If you want to ensure your wealth is supporting realistic, science-backed climate solutions, Book a FREE Call for a quick chat about ethical portfolio construction.

The goal is not to chase the most futuristic idea. It's to back the solutions that can actually get us there.