> There's also the issue of the mass of batteries not going away during the flight Excellent point; currently as fuel is burned off, planes can climb to higher

> There's also the issue of the mass of batteries not going away during the flight Excellent point; currently as fuel is burned off, planes can climb to higher, more efficient altitudes (known as a step climb). What's the performance penalty for not being able to do this as your batteries aren't getting lighter as the flight progresses.