This is a weird and memorable flight. I now have done it twice, once in coach and once in business.

But we did encounter one apparent change, between the first journey on EY171 (last summer) and the second (yesterday) — the route became something that stretches our understanding of the planet.

There it is, above, on the map. Check it out.

When was the last time you took a plane that flew north of Greenland?

Two things about that bit of information:

1. My recollection of the first time we took EY171 was that it crossed Greenland, about halfway up the island.

2. It does strike the traveler that if Something Happened, during the middle of the 16 hours and 40 minutes that is EY171 … you would be very far from the nearest commercial airport able to handle a Boeing 787.

As usual, the flight was late. This time by 70 minutes, nearly all of which we spent sitting at the gate. Just what you need. Another hour-plus on a plane that is going to do 16 hours and 40 minutes with the wheels up. (Update: EY171 two days later took off six-and-a-half hours late.)

Why Etihad doesn’t just say, “OK, this flight is at 10:20, not 9:20” … is inexplicable. If it’s late something like 80 percent of the time … own it!

Even when it’s on time, it is really long.

Imagine flying from Los Angeles to New York … and then turning around and flying back to Los Angeles … and then turning around and flying back to Chicago — and you almost have a flight as long as EY171.

This time of year, this involved a 12-hour time change. If it actually takes off on time, at 9:20 a.m., that’s 9:20 p.m. the previous day in Los Angeles.

I found it interesting to reach the midpoint of the flight — eight hours and 20 minutes into it. I had the “course map” app up on the seat-back screen, and as it flicked through the “time since leaving Abu Dhabi” … “time to Los Angeles” … I did a mini-celebration when the first number finally was larger than the second.

I had eaten a meal, watched Bridge of Spies (thumbs up) and slept for three hours before we reached that midpoint, somewhere over the Arctic Ocean.

OK, so I mentioned I was in business class (paid for by my former employer). Which hugely improves the chances of not losing your mind during this flight. Your own little pod. A seat that reclines and turns into a bed. Food and drink on demand from the flight staff — when you can find them.

In addition, the main part of the “business” side of the cabin was nowhere near full. I counted 14 empty seats among the 32. So we didn’t even have a sense of “someone sorta nearby”.

The two seats at the rear of the compartment were empty, allowing me to take a lap of this part of business class, making the turn at the staff’s food-preparation area, which didn’t seem to amuse them, but it’s good for your legs.

And each time I reached the back of the compartment I took a peek through the curtains dividing business from coach. Mostly because I was thinking of making a longer lap, all the way to the back of the plane.

And each time I was semi-horrified by what I saw. What looked like a full house in coach. In that brutal 3-4-3 seat arrangement that is the worst aspect of the Dreamliner — which is what the 787 is called by Boeing, clearly by people who have not spent something like 18 hours in that 3-4-3 torture chamber.

On my first peep at them, I saw some poor sap in the middle of the starboard side “3” with a blanket over his/her head in an attempt to sleep through at least part of the nightmare.

And then as I took my place again in 11E, I pondered, for a bit, the social cords that keep 170-some people stuck to their cramped stations when we had 14 empty seats (at least) in business.

What would happen if 14 people from the back just pushed aside the curtain and sat in the business seats? Who was going to stop them? The little flight attendants with the odd accents? Would the pilots have put the plane down on some Arctic ice floe and summoned authorities?

I also find interesting the timing of activities.

Shortly after takeoff, dinner was served. At about noon, body time, and soon after, the lights were turned off — an encouragement to sleep. And the lights were left off till the end of the flight. Meaning we were supposed to sleep for 15 hours?

A second, smaller meal was served about halfway through the flight … and that was it for food. (Unless you were in first class or business, and could ask for snacks, or asked to delay one of your meals.)

Anyway, it is hard to tell what time the airline was trying to get us to adjust to. (Probably the time that best suited their management of 300 people stuck in a metal tube.)

Much of the crew seemed to disappear, after the second meal, and even in biz class the flight attendants stopped circulating. Do they have quarters in the hold? I need to investigate this.

So, we were an hour late, and beat up and frazzled — and that was the people in business class. I hope the folks in coach were young and had been well-rested when we took off, because nearly 18 hours in the plane, when we factor in the late start, is just about unbearable for anyone else.

It may be the shortest and fastest way to get from Abu Dhabi to Los Angeles, but maybe breaking it up into two flights would be less punishing, if longer.