Ah, so just like off-the-shelf RC planes at the moment, then :)
Batteries are heavy. Gasoline has tons of energy for how much it weighs. New battery tech shows up on HN all the time and I've never seen one come to market. LIFePO4 and other similar lithium chemistries are still state-of-the-art in terms of what you can buy right now.
"Indeed, the theoretical specific energy of a non-aqueous Li-air battery (in the charged state with Li2O2 product and excluding the oxygen mass) is ~12 kWh/kg. This is comparable with the theoretical specific energy of gasoline (~13 kWh/kg). In practice, the Li-air batteries with a specific energy of ~1.7 kWh/kg at the cell level have been developed."
"However, the areal power and cycle life of lithium–oxygen–air batteries need significant improvements before they can find any competitive market niche."
So, they're still an order of magnitude away from gasoline and you can't buy one today (or probably in 20 years either).
To be fair, electric engines are much more efficient than internal combustion engines, so you don't need to achieve the same specific energy to achieve comparable outcomes.
But, to be realistic, one of the startup "stars" of the battery scene, Envia, is marketing an aviation battery with 0.35 kWh/kg, so I'd say that's realistic state of the art. So, even getting the 1.7 kWh/kg you mentioned in a production-ready battery would be huge.
Batteries are heavy. Gasoline has tons of energy for how much it weighs. New battery tech shows up on HN all the time and I've never seen one come to market. LIFePO4 and other similar lithium chemistries are still state-of-the-art in terms of what you can buy right now.
https://en.m.wikipedia.org/wiki/Energy_density has a comparison. Lithium air batteries are in the extended reference table here https://en.m.wikipedia.org/wiki/Energy_density_Extended_Refe...
From https://en.m.wikipedia.org/wiki/Lithium–air_battery :
"Indeed, the theoretical specific energy of a non-aqueous Li-air battery (in the charged state with Li2O2 product and excluding the oxygen mass) is ~12 kWh/kg. This is comparable with the theoretical specific energy of gasoline (~13 kWh/kg). In practice, the Li-air batteries with a specific energy of ~1.7 kWh/kg at the cell level have been developed."
"However, the areal power and cycle life of lithium–oxygen–air batteries need significant improvements before they can find any competitive market niche."
So, they're still an order of magnitude away from gasoline and you can't buy one today (or probably in 20 years either).