Boarding slows down when people need the same piece of aisle at the same time. This experiment changes the order of arrival while keeping the passengers, seats, bags, and individual stowing times identical.
The Steffen method
Physicist Jason Steffen proposed spreading passengers along the aisle so several can put away luggage at once. Window-seat passengers board before middle-seat passengers, then aisle-seat passengers. Alternating rows give neighboring travelers room to work.
Here, each seat column boards from back to front in even rows, then odd rows, in the order F, A, E, B, D, C. For example: 20F, 18F, 16F … then 19F, 17F, 15F … before moving to column A. Empty seats are skipped.
Back to front
The last row boards first, followed by the next row toward the front. Within each row, this model uses the fixed seat order A, B, C, D, E, F. People tend to arrive at the same area together, which can concentrate luggage delays. This is a strict row-by-row model, not a simulation of every airline’s boarding groups.
Random boarding
The same passengers board in a shuffled order. Seats are still assigned: “random” describes the queue, not a choice of any seat. People naturally spread out, but someone in an aisle seat may already be sitting when their window-seat neighbor arrives.
What happens inside the cabin
- Walking and spacing. Movement advances in one-second steps, at three seconds per row, with about one row of aisle clearance. Everyone enters through the front door, shown at the bottom.
- Taking a seat. Seating takes four seconds, plus seven seconds for each already seated passenger blocking the route from the aisle.
- Finding a bin. Passengers prefer their own two-row bin section and side. They reassess nearby space while walking, without reserving it. A candidate must be within four rows of their seat, no more than one row beyond it, and between roughly two rows behind and four rows ahead of their current position.
- Stowing a bag. Each bag takes one slot. A slot turns white when claimed, at the start of stowing. The chosen stowing time and variation determine each passenger’s duration.
- Crew assistance. If no suitable nearby bin is available at the seat, the passenger waits for the selected average stowing time plus 20 seconds. The model then places the bag in available storage, possibly farther away. A crew member’s actual route and competing workload are not simulated.
- Passing. Two people walking in opposite directions can pass after the selected delay. One crossing counts as one pass. Someone stowing a bag blocks the aisle; waiting behind them is not a pass.
Why fewer passes does not always mean faster boardingSteffen aims to reduce waiting by allowing simultaneous stowing. It does not create extra bin space or guarantee fewer crossings. Near-full bins can still require help. Compare total time, bag distance, and crew assists as well as passes.
Reading the display
Blue: walking or waiting in the aisleAmber: stowing or awaiting crew helpPurple: passingGreen: seating or seatedWhite: occupied bin slotGray: empty bin slot
Gray seat rectangles are assigned but not yet occupied. Darker rectangles are unassigned. Colors represent passenger activity, not the boarding method. Text counters provide the progress alongside each animation.
Bag distance is the average row distance between a seat and its stored bag. During a flight it covers bags already claimed; at completion it covers all overhead bags, including crew-assisted placements. It measures row distance only, so a bag on the opposite side can still be zero rows away.
How to make a fair comparison
- Adjust the flight conditions. The baggage slider is capped so all bags fit somewhere on the plane.
- Select Start all. The three methods share one simulated clock. Pause, resume, or change playback speed whenever you like.
- Reset replays the same passenger arrangement. New passengers creates another arrangement with the same conditions.
- Select Compare 20 scenarios for average boarding time, passes, bag distance, crew assists, and outright wins. Every trial shares its travelers across methods; assignments change between trials.
The scenario number identifies a repeatable random seed. A repeated comparison uses the same 20 arrangements until you change the conditions or choose New passengers. Tied fastest finishes are reported separately. Arrangements that exceed the time limit are excluded from every method’s averages, and the excluded count is shown.
Assumptions and limitations
This is an exploratory model, not a forecast of airline boarding times. It retains the revised rules from the original comparison. Passengers follow their prescribed order perfectly; the clock starts at cabin entry and excludes time spent organizing the queue at the gate.
All travelers have the same walking speed and at most one equal-size overhead bag. Families, priority groups, mobility needs, late arrivals, multiple doors, variable bag sizes, and real crew movement are not represented. Simplified spacing, passing, and assistance can change the relative results. Twenty arrangements reveal some variability but are not a statistical validation or a confidence interval.
Read the research
The method’s motivation comes from Jason Steffen’s 2008 boarding paper. Steffen and Jon Hotchkiss later published an experimental comparison of boarding methods. Those studies inform the explanation; the times you see here are generated by this simulator.
Boarding Lab is an independent educational site. It is not an official OpenAI or airline website.