Airline starts weighing passengers: Here's why

(NewsNation) — If you've flown recently, you know the motions you'll need to go through before boarding your plane. Check your luggage, pass through TSA, show your driver's license, scan your boarding pass. What about stepping on a scale?

Many reacted less-than-fondly to an announcement earlier this month that Korean Air, a South Korea-based airline, planned to weigh passengers before boarding.

A representative for the airline told CNBC the practice would last for about three weeks, and is required by law. All Korean flag carriers have to weigh passengers and their carry-ons at least every five years to ensure safe flying operations, the representative explained.

Passengers will be weighed anonymously, Korean Air said, and passengers can opt out.

So can you expect to find yourself on a scale before boarding your next domestic flight?

Likely, no, but it isn't impossible.

The U.S. does not require airlines to weigh passengers as South Korea does. However, a 2019 advisory from the FAA said airlines can weigh passengers, according to CNBC.

"It allows us to have actual accurate and current, up-to-date weights for our particular flight," Captain Laura Einsetler, a commercial airline pilot with more than 30 years of aviation experience, told NewsNation. She noted that there are multiple factors that can impact a flight, like runway length, altitude, air density, weather, and cargo weight. "So when we have the more accurate weights, we can make better decisions about aircraft performance."

As Einsetler explained, airlines in the U.S. rely on assumed weights for the summer and the winter seasons. It also incorporates passenger and carry-on weights.

Others have weighed passengers before.

New Zealand's Civil Aviation Authority asked its airlines to weigh passengers in July, to gather weight load data, CNN reported. Hawaiian Airlines and Finnair have previously done the same.

In the early days of air travel, Airlines frequently weighed passengers and even crew to properly balance the smaller, less sophisticated aircraft, according to the Smithsonian.

Passenger weight can have an impact on another aspect of flying: seat size.

There is no minimum width, length, or distance between rows of seats required by the FAA, with many still the same dimensions they were in the 1980s, when Americans were smaller. Last year, the FAA asked for passengers to give their opinion on airline seats, garnering thousands of responses that complained of narrow rows, small seats, and insufficient legroom.

No new regulations have been enacted in response to the comments.

Michael Bartiromo contributed to this report.