
Instead of fumbling with task of explaining the concept of aerodynamics myself, I will simply lift some copy from the Porsche 924 ad seen below. Per Porsche:
Air resists the movement of a vehicle passing through it. Resistance increases with the square of the vehicle’s speed: twice the speed produces 4 times the resistance. The engine power required to overcome this drag increases with the cube of the vehicle’s speed: twice the speed requires 8 times higher power. Thus, even a small reduction in drag can result in a large increase in fuel economy. Dr. Ferdinand Porsche was among the first to reduce drag through body design. The Porsche 924 benefits from 70 years of Porsche aerodynamic development. It’s drag coefficient is a low .36. And it requires only 15 hp to cruise at 55 mph.
Two observations about the Porsche text. First, it’s clear Porsche copywriters don’t like commas. Second, this blurb ignores the 1921 Rumpler Tropfenwagen—a vehicle largely understood to be the first intentionally aerodynamic car. And, it boasted a better coefficient of drag than the 924. You can read all about the Tropfenwagen here.

Looking back, it’s clear that long before carmakers were making effective use of aerodynamic design, they were laying claim to having harnessed the virtues of low-drag silhouettes. For your consideration, we have amassed a gallery of classic ads, each of which touts the benefits of streamlining and aero design in some fashion. Check them out, and let us know which is your favorite. For the record, the Tatra ad—which is an ad, not a brochure—is absolutely my favorite.
Automotive Aerodynamics
1932 Rockne

Market Crash Madness! A Gallery of Depression-Era Car Ads
1934 Chrysler Airflow

Amazingly Innovative Cars . . . And Why They Failed
1934 Kestrel

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1934 Hupmobile

Photo Feature: 1933 Hupmobile K-321 Convertible Coupe
1934 Tatra

1935 LaSalle

Designer Madness! Fashion in Classic Car Ads
1949 Nash

Plaster Master: Salvaging a Nash Styling Model
1952 Willys

Photo Feature: 1941 Willys 441 Station Wagon
1956 Plymouth

Photo Feature: 1960 Plymouth Fury Hardtop Coupe
1968 Chevrolet

1976 Plymouth

1978 Toyota

Aichi Madness! 10 Classic Toyota Ads
1980 Porsche

Review Flashback! 1973 Porsche 911
1981 Buick

Cheap Wheels: 1979 Buick LeSabre Palm Beach
1981 Buick

Dynaflow Madness! A Gallery Of Classic Buick Ads
1983 Pontiac

5 Most-Powerful American Cars of 1980
1983 Mercury

What Was the Mercury Cougar Bostonian Edition?
1984 Audi

Gallery: Cool Cars at Fun Places
1985 Ford

Review Flashback! 1984 Ford Thunderbird Turbo Coupe
1986 Ford

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Automotive Aerodynamics Gallery