Yes, they are real words but they're used mainly by people in the transport industry, and I suspect that they were originally made up by the industry.

Of course, most people simply "get off the plane" or "get off the train" or "get out of the bus" or whatever - although bus and train companies sometimes like to talk about their passengers "alighting". But rather mysteriously, it seems that that airlines don't talk about passengers "alighting from the aircraft", do they?