I think I would be hard pressed to say maintenance free but definitely significantly lower maintenance costs. Turbine blades are intrinsically expensive, made of titanium and operate at high temperatures under high loads. Electric motors have much simpler operation and when made at scale, can really benefit from a replace after 20,000 hours model, instead of a overhaul every 1800 hours, with 200hrs inspection intervals, which we see in some turboprop engines. Fuel cells and batteries are much the same, replace after a certain life, and with built in tolerance to failures. Unfortunately, with fuel cells, as opposed to batteries, we still have some balance of plant that will need maintained, compressors for example, however unlike a turbine engine, they don't operate at high temperatures and are a smaller part of the system, so we can design for much longer lifetimes that you can get away with in a turboprop. All this leads us to estimating 65% saving on engine maintenance. Battery electric companies are going after more like a 90% saving.