How much could US air carriers lose thanks to the EVAC Act?

Removing seats to make aisles wider will be costly, but maybe not by as much as you might think

One of the more eyebrow-raising pieces of airline news I read over the summer was about the Emergency Vacating of Aircraft Cabin (EVAC) Act in America.

Tammy Baldwin and Tammy Duckworth, the junior senators from Wisconsin and Illinois, have identified a clear problem: big people take time to get out of small seats, which could cause delays and even cost lives in an emergency. They doubt a 90 second evacuation required by regulators is feasible in practice.

The two senators are calling on regulators to be more realistic regarding seat size, including wider aisles for wheelchairs. Wider aisles with seats big enough for plus-sized passengers will inevitably mean losing a seat per row.

We don’t cross the Atlantic much at Airline Revenue Economics, hence the rather out of date picture at the top of the article. This was the only image of a US registered single-aisle in my collection!

Endless single-aisle services shuttling back and forth between Wisconsin and Illinois, Ohio and Florida or Missouri and Colorado make few hearts race. US carriers are not renowned for either their innovation or the passenger experience.

When it comes to the EVAC Act, which is in fact still a bill and not an Act so is not (yet) the law, airlines and their friends will likely scream that it will cost them money.

The question is, how much money? Thanks to revenue management, it is not simply a case of losing revenue in proportion to seats removed. This makes EVAC a most interesting topic for your favourite airline revenue economist.

I used my LOOP models, which use the principles of revenue management to evaluate aircraft interiors projects (see article), to find out…

Data & model overview

I used a number of data sources to populate my model:

1. FlightRadar24 aircraft movements: I wanted to understand how aircraft circulate around on US domestic routes and took a sample of nine single-aisle planes, three each from American Airlines, Delta and United, for the week 29-Aug-23 to 5-Sep-23.

2. Aerolopa seat maps: To figure out how many economy (or coach, since we are in America!) class seats would need to be taken away to make aisles wider I used the plans available on Aerolopa

On American Airlines’ Airbus 321 and United’s 737 I modelled removing one seat from each row on the right hand side of the plane. For Delta’s 737 I modelled removing one seat per row on left hand side and one seat from the last row on the right hand side.

3. ATPCO fares data: To get an idea about how much airlines receive for each seat, I looked at fares for return itineraries on all of the routes that each aircraft flew, departing 5-Sep-23, returning 12-Sep-23 and based on fares filed on 4-Sep-23 quoted in US Dollars – in my model there are 7,423 fares across 241 flows, more than 30 fares per route.

I understand that these airlines tend not to charge YQ surcharges (see article) on the domestic routes so the fare should be representative of what the airlines receive (less discounts and commission, more on that later).

The maps below show how the aircraft moved across North America during the sample week. Only one aircraft, United 737 N73496, operated entirely two and from one market, Houston. The others all moved around a great deal. The tables below the maps show some key statistics.

Note: ANC, SAL and SJU are anchoring points to ensure that each aircraft’s movement is plotted on an identical map. Only N826DN flies to ANC, only N903DN flies to SAL and only N69826 flies to SJU in the week I studied.

The schematic below shows how I used the three types of data, together with three whizzy revenue management algorithms, to calculate how much money airlines could lose on their domestic aircraft if the EVAC Act takes effect. It is a big number as you might expect, but perhaps not quite as big as you might think…

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