Comparing fuel efficiency of a personal automobile to an aviation mass transport is not meaningful. A bus will sure be a lot more fuel efficient than an airplane. However, a bus travels probably ten times slower than an airplane (which means a bus uses a lot less energy, that's why it's more fuel efficient). Furthermore, surface transportation requires significant more infrastructure than air transportation. Thus, taking everything into account (time, infrastructure, fuel, etc.), air transportation is most definitely a more efficient means for *long-distance* travel (here long can be just a few hundred kilometers).