Popular for a brief time? The most popular small airplanes in the world still have fixed landing gear and "pants".

This.

I’m regularly in the 40s on many of my gravel rides and have been into the 50s on roads I know.

Plenty of rolling / flats where you can cruise along in the 20s on 40mm treaded tires.

UCI regs:-

"the addition of a fairing to cover chainwheels, chains or any other moving part of the bicycle is prohibited."

Obviously nothing to stop fairings being used outside of competition, but then people who want to ride competitively fast are going to want a UCI compliant bike.

He's an original thinker with interesting ideas. Sometimes the data support his ideas.

Where did I say that they weren't?
So a little better details of what you are learning might help. It's going to be difficult to attribute whether the differences are rolling resistance or aerodynamic.

I think that anyone riding a bike that tracks their data will be able to tell if a particular tire does better for them or not. Doesn't matter if it's because it's more aero, lighter or less rolling resistance or some yet unknown factor. Find the best tire for you and it won't matter why that's the best tire.

That's fair. My initial question was wondering if tread pattern on road tires makes a difference. Apparently it does, to some degree. In the real world, it probably won't make any difference in my life, or even in my tire choices. This was an exercise in expanding my knowledge.

A petty real world example?

I wanted to get the KoM on a 3 mile very slightly downhill segment with several tricky turns, the only course a fat old albeit experienced rider might be able to snag a KoM.

With the superfast Vittoria Speed tubeless tires, I was always something like 4-6 seconds short of the KoM. I put Conti on and beat those times every single attempt and got the KoM. The Conti tires did not quite roll as well but at 32-35 mph, they must have been better aerodynamically despite being slightly wider (1mm actual). I swapped to those tires because a Nat TT champ told me they were the fastest. So, I won my rinky dink KoM.

How 'bout sharing the actual models of the tire along with the size.

And how do you decide if it's the aerodynamics or that the tire gripped better during turns giving you more confidence or other such?

This is where science matters ... the result was a KOM, and the Means were the Contis over the Vittorios .... BUT ... the "control" was only over tire brand and overall performance, and no measurements were made to quantify Why the tires were apparently faster.

Maybe they did roll better at some speed, or maybe they gripped better in turns .... six seconds over three miles sounds like a pretty big aero improvement, particularly since the tires probably had a higher profile .... were they better matched to the width of the rim? That might have been more of a factor than the tread pattern or tire size. Did you try the Vittorios at varying pressures?

All we know is that You, on That course, using Those tires, were six seconds faster on That day. The "Why" has not really been addressed in detail.

Congrats for the KOM, but don't make the mistake of asserting that the tires must have been more aero when there is absolutely zero evidence ... I would say.

So the "any other moving part" covers wheels meaning fenders as a fairing are out?

If you won't buy a fully faired bike, you could still buy these.

That is a very good question.

There was another somewhat similar Strava segment with only one turn and I nabbed that one too.

I know from rollout tests the Vittoria Speed had lower rolling resistance and also Brr showed the same order. I would have had to do Chung testing but taking tubeless off and on to do ABBA testing would have been excessive even for me. The other reason I tried those tires is because a German Forum devoted to Velomiles found that casing to be the best at high speed. Crr increase with speed, load, and decreasing temperatures. The German guys seemed pretty smart. So what the hell, I tried it. But your point is taken. In General, Vittoria tires of late corner very well per Brr grip tests and my seat of the pants "feeling"

Lots of mention of headwinds. Zero mention of crosswinds. Hmmm....

I'm guessing you'll get pushed around quite a bit.

The guy in the road test video implied the bike was easier to steer with the fairings.

Okay. I didn't look that far. That said, I'm still doubtful.

If only there were some way to measure putative improvements in the field.

LOL. I get it. My doubts aren't based on anything more than an uneducated assumption related to my experiences with deep-section wheels. I'm probably wrong.

I meant, both the Nullwinds guy and Jan Heine think coast down testing is a good way to measure differences. Coast downs done well and carefully can be, but those videos don't show carefully done coast downs.

Didn't read all the replies, so someone may already have mentioned it, but I remember reading somewhere that mounting your front GP4000 backwards is good for maybe a watt.

That's how I would read into it.

That is terrifying! I worry about something on the pavement going through sweeping corners on a fast decent. I can’t imagine doing that on gravel! To be honest I don’t think I’ve ever hit 47, maybe 43-44mph?

are you going to be racing in an officially sanctioned event for the need of more aerodynamics?