Passenger Airplane Efficiency

A friend and I were wondering about the efficiency of traveling by passenger airplane.  Again a Wikipedia article comes through and says somewhere around 49 mpg per passenger back in 1998 but efficiencies have been improving since then.  I wonder if that includes the ridiculously long times the airplanes sit at the gate or taxi around with their jet engines on.  Hopefully Airbus and Boeing will be able to license Toyota's hybrid synergy drive so people can feel good about themselves as the electric motors take over while taxiing at the airports.  Then everyone in the cabin would be talking about how they can't even tell the airplane is on.