How are bags transported from the terminal to the airplane? I'm curious how bags are transported from the terminal sortation system to the aircraft. I'm mostly trying to understand the &quot;average tarmac distance&quot; a bag will travel. If anyone has direct insight into that metric that might be even more helpful than understanding the process.
I grabbed a screenshot of the United Terminal at DIA to try to map out how this could be implemented. Can anyone help with insight into which process implementation is generally used in the industry?


Each gate has a &quot;sort point&quot; and bags are transported a short distance from that gate sort point to the plane parked at the gate.



One sort point serves &quot;N&quot; number of gates. One baggage handling Cart serves only one plane. (How big is &quot;N&quot; if this method is used?)



One sort point serves &quot;N&quot; number of gates. One baggage handling Cart may serve several planes, detaching a section of the the train at each craft.

Are any of these methods used? Or perhaps could several sort points feed one aircraft? Does this vary airport-to-airport or airline-to-airline? Who is generally responsible for the design of the process - the airport or the airline? Do ULDs have a different process than each-loaded bags? What about smaller regional jets loaded at the far ends of the terminals - are their sort points further away? How does the process look for offloading bags from the aircraft?
From your photo this answer assumes a hub airport.
Some background first: after check-in, the belt conveyor system moves each bag onto its own tray – that's the modern individual carrier system (ICS) which mitigates jams, misreads, and lost baggage. Depending on how early the check-in took place, the tray will either go to a holding area, or directly to the baggage makeup area/space (BMA) where the bags are unloaded onto another belt conveyor system for cart/ULD loading.
BMA is the place you referred to as sort area. There is typically one BMA per airline per pier, and since big airlines usually have their own piers, it's one BMA per pier. Example for San Francisco Intl (see tan colored areas):


— https://www.flysfo.com/about-sfo/sfo-tomorrow/passenger-terminal

Two hours or so before the flight's STD (scheduled time of departure), comes the cart/ULD staging. The cart train length varies; IATA recommends 3 carts per narrow-body and 5–6 per wide-body. Airlines however implement this as best fits them. Easyjet for example stages one cart per narrow-body at Liverpool (internationalairportreview.com).
Regarding how many gates are served per BMA, one of the methods used to estimate the floor area required for a BMA when designing an airport is the EQA, or Equivalent Aircraft factor (see FAA AC No: 150/5360-13 for more).
In short, it's option 2.