Since November 2014, passengers flying from Frankfurt Airport on Lufthansa’s Boeing 737s have been the first in the world to experience an innovative technology without, perhaps, even realizing it. The airplanes have been pushing back from the gate and taxiing to the runway as usual. But on these flights, the 737s have been rolling from the ramp to the runway without the use of the aircraft engines. Under the control of the pilots, the jets are being towed by a semi-autonomous aircraft tractor called TaxiBot.