The decades-old idea of electric-powered commercial flight has re-emerged along with high expectations for greener air transportation. To what extent can electric aircraft reduce the energy and environmental footprint of aviation? How should they look like and how does their operation compare to conventional jet aircraft? What technologies are needed, and which of them are already in place? This paper goes back to basics and analyses critically some of the unresolved challenges that lay ahead. Current commercial operations are examined and the short-term effects of electrification are identified. Fundamental components, basic design and operating concepts are analysed to highlight unavoidable constraints that seem often overlooked. These limitations are illustrated with a conceptual study of a full-electric FAR/CS-23 commuter and realistic estimations of its performance. It becomes clear that electric propulsion alone will not fulfil the expected goals, but it might be one more step on the way.