(In the US) for airplanes with a maximum gross weight over 12,500 lbs, you require a "type rating" on your license to fly the plane. The type rating is for a specific make and model (type) of airplane. So if you have an Airline Transport pilot certificate with a 777 type rating, you cannot legally fly a 757 (unless you have a 757 type rating)
This distinction shows up not just in the law. I have many hours flying a Cessna 172, but when I recently bought a 182, some insurance quotes required as much as 10 hours of instruction, even though I could legally fly the 182 without any at all.
(Disclaimer: I haven't actually flown large airplanes or driven tractor trailers - someone more experienced is welcome correct what comes below)
Tractor trucks are all pretty similar. Hydraulic power steering, air breaks, unsynchronized transmissions, one engine, 18 wheels. They have similar stopping distance, similar handling around turns, and nearly identical controls.
Large planes on the other hand can have very different handling characteristics and controls. Different approach speeds, different after-takeoff checklists, different emergency procedures. Different navigation and autopilot systems. Fly-by-wire systems even change the basic relationship between control inputs and their effect on the plane.
There might be a special case for the 737 & 777. What I have read is that Boeing designed the cockpit of the 777 to match that of the 737, and so the type rating is mostly transferable between the two.
This distinction shows up not just in the law. I have many hours flying a Cessna 172, but when I recently bought a 182, some insurance quotes required as much as 10 hours of instruction, even though I could legally fly the 182 without any at all.
(Disclaimer: I haven't actually flown large airplanes or driven tractor trailers - someone more experienced is welcome correct what comes below)
Tractor trucks are all pretty similar. Hydraulic power steering, air breaks, unsynchronized transmissions, one engine, 18 wheels. They have similar stopping distance, similar handling around turns, and nearly identical controls.
Large planes on the other hand can have very different handling characteristics and controls. Different approach speeds, different after-takeoff checklists, different emergency procedures. Different navigation and autopilot systems. Fly-by-wire systems even change the basic relationship between control inputs and their effect on the plane.