Sustainable transportation and aviation are critical to address climate change and renewable energy powered battery electric vehicles represent a promising path towards this goal. I will discuss the performance metrics needed of batteries for electric land and air vehicles, and assess the energy-efficiency of electric vertical take-off and landing (eVTOL) aircraft compared to ground vehicles. Identifying the challenging but achievable battery performance requirements for eVTOL, I will discuss our approach to achieve simultaneously high specific energy and power by using lithium metal anodes, enabled through a new density-driven dendrite suppression mechanism realized through a soft polymer-ceramic composite separator. I will discuss the unique performance failure mode related to power fade for eVTOLs rather than energy fade for electric vehicles. Following this, I will discuss the requirements and challenges for all-electric battery-powered single and twin-aisle aircraft and outline battery chemistry innovations that offer a pathway to approaching these requirements. I will discuss two key tools to accelerate the innovation timeline for these battery chemistries: (i) in-situ and operando characterization and (ii) closed-loop battery material discovery with physics based simulation and robotic experimentation.