Funny, the things you don’t notice when you board a 5:15 a.m. flight.

You barely see the flight attendants who give you a cheerful greeting as you enter the cabin.

You don’t notice one of your co-workers sitting a few rows behind you.

As usual, you don’t pay attention to the seat belt instructions and you only half listen to the warning to turn off all Samsung Galaxy Note7 smartphones, due to battery problems.

Hey, I have an iPhone. That one didn’t apply to me.

Or so I thought.

Shortly after Delta Flight 2557 took off from Norfolk International Airport on the morning of Sept. 16, the captain dimmed the cabin lights and some of us tried to catch a nap on the way to Atlanta. For many, it was the beginning of another ORF-hopscotch journey that would involve a series of short, expensive flights and layovers.

I leaned my head against the window and stared into the darkness as the lights of Hampton Roads disappeared beneath us.

After about 15 minutes in the air, there was a commotion in the rear of the cabin. Two flight attendants ran down the aisle, their shoes pounding the deck.

The cabin lights flashed on. There was a vague, acrid aroma of smoke.

Fire.

Later, we’d learn it had started with a lithium battery disconnected from a cellphone or other device in row 34. This was just one day after the Samsung phones had been recalled because of fears the batteries could catch fire.

In an instant, three flight attendants switched from smiling enjoy-the-flight hosts into tough, professional first-responders.

Passengers who’d been gawking at the smoking battery were immediately herded to the front of the cabin and told to sit or kneel in the aisle. And stay there.

One crew member called for a halon fire extinguisher.

I was in row 26. A woman behind me began to hyperventilate. One flight attendant stopped to comfort her, then returned to the source of the smoke.

Chances are you read about our flight. It made national news as well as The Virginian-Pilot.

A spokesman for Delta told me Tuesday the incident was still under investigation. The source of the battery remains unknown.

I learned a lot about lithium fires after that flight by talking to experts. How hot they burn. How quickly they ignite. How difficult they can be to extinguish.

“Oh my gosh, a lithium battery fire in a very confined space,” exclaimed Mark Hundley, a Virginia Beach master firefighter and hazardous materials specialist , who told me that both water and oxygen feed lithium fires. “That could have been very hard to control.”

I tried to imagine what might have happened if the battery had been in a checked bag. Then I tried to imagine what would have happened if the flight crew hadn’t known what to do.

Delta spokesman Michael Thomas told me Tuesday that the airline’s roughly 23,000 flight attendants receive seven weeks of safety and security training before they ever come into contact with passengers. In grueling six-days-a-week, 12-hours-a-day training sessions, they learn how to deal with a stunning array of emergencies: fires, heart attacks, unruly passengers, extreme turbulence, crashes and water landings. Flight attendants are required to pass a series of tests with a 90 percent grade on every one.

They also take refresher courses.

“It’s intensive,” Thomas said of training. “We want it to just kick in, so no one has to stop and think about what to do or check a manual.”

That’s exactly what happened on that morning almost two weeks ago. The no-nonsense demeanor of the crew members told us that the situation was serious, while their composure assured us they knew what they were doing.

They were putting out a fire. We needed to give them room to do their jobs.

Eventually the battery was extinguished. Passengers who’d been ordered to the front of the plane were allowed back to their seats. A smiling flight attendant checked again on the distressed passenger behind me.

There was no beverage service on that flight. No tiny bags of nuts.

Funny, I didn’t hear anyone complain.

A version of this appeared in The Virginian-Pilot on Sep 28, 2016.