Seems a silly idea, but... loading an electric “bus” at a population center would prevent the emissions of individual vehicles driving to the airport. Upon arrival at the ramp, all people and luggage would already be stowed, so there would be less delay — and they wouldn’t need a gate — meaning more airport operations per hour might be possible. (Although, usually, runways and required separation of air traffic are the limiting factors.) Could increase flights without building another terminal.
I assume the bus “tractor” is electric, and would be separated from the passenger pod and remain behind at the airport. Then, as long as the bus doesn’t become detached from the wings during flight... there you go. Maybe someday, when all-electric planes use swappable batteries, swapping an entire bus-like module like this might make sense.