Boeing (Chalet 321, 324) is wrestling with the problem of designing an aircraft that’s too big to be a single-aisle and too small to be a twin-aisle. CFM International (Chalet 121) and Pratt & Whitney (Chalet 338, Static C2) are dueling over the 20,000-30,000-lb. engine market. Fort Worth wants to take over the entire Western world’s fighter business.

And there are two supersonic airliners flying at Le Bourget. Wait, what?

Paris 2015 has some strong echoes of Paris 1975, which was the first time I was here, as Flight’s air transport reporter.

As such, I did not get to cover the real scene-stealer of the show. That was General Dynamics’ Neil Anderson, performing a demonstration in the only flightworthy YF-16 (the other one was being repaired after Anderson had had a landing gear failure at Fort Worth) that was physically impossible for any other airplane. It had been one thing for those bomber-factory farmboys to clean Northrop’s clock in the U.S. Air Combat Fighter competition. But by May 1975 the F-16 had routed a disorganized European opposition, replacing F-104s and F-5s in much of Europe.

If you’d told anyone in 1975 that we would be arguing about the F-16’s replacement 40 years later, you would have been right, but everyone would have thought you were out of your mind.

But Boeing’s “middle of the market” 200-seater dilemma is as simple as it was then. A single-aisle, six-across 200-seat airplane is long, hard to load and unload and unattractive to passengers, but the twin-aisle is short, fat and heavy.

Boeing’s solutions in 1975 were influenced by the company’s strategic goal, which was to sell new-model airplanes to Lufthansa and British Airways and deliver the coup de grace to upstart Airbus.

As a Boeing VP had told me a few months earlier: “It’s a typical government airplane. They’ll build a dozen or so and then go out of business.” (This is why they pay VPs so well.)

There were two new Boeings in model form at Le Bourget and neither of them was ever built. The 727-300B was the final iteration of studies that had started in 1974, with JT8D-200 engines, four-wheel main landing gear bogies and a heavily modified wing. Boeing thought it was within months of launch.

The other new project was the 7X7, which introduced the seven-across cabin of the 767 but had three engines, either CFM56s or Pratt & Whitney’s JT10D. The smallest, shortest-range version clearly overlapped in size with the 727-300B, but Boeing was quite insistent that it might build both. The 7X7 was intended to run later than the stretched 727, and was an advanced-technology design, intended to have (gasp!) a two-crew digital cockpit using cathode ray tube displays.

Some of us saw 7X7 as a conveniently remote technological panacea, a shiny object to distract the market (like the later 7J7 and Sonic Cruiser) while Boeing killed Airbus with the 727-300B. It didn’t work. United, the intended launch customer, balked and the project was dead by September.

The 7X7 would morph into the twin-engine 767, but to everyone’s surprise (including Boeing’s) mostly flew as a long-haul 707-replacement. For shorter routes, the airlines stayed with narrowbody aircraft: the 757 was quite close in payload and range to the 727-300B. Anyone want to bet whether the “middle of the market” will split in two again in the 2020s?

But the 7X7 was a morale-booster for the CFM56. Snecma President Rene Ravaud was optimistic about its future at Paris, but nearly everyone else was waiting (with ill-concealed glee) for the project to fall on its nose. Ravaud’s description of aircraft like the Airbus A300 as “beautiful pieces of tin” with American components made him few friends. Rolls-Royce (Chalet 93), which regarded his CFM deal as treachery, was ready to join P&W on the JT10D.

Four years later, the CFM56 was finally sold (for re-engining DC-8s) when GE (Chalet 142) and Snecma were within weeks of pulling the plug. Unconvinced that there was a big market, P&W redesigned the JT10D into the larger PW2000 and (together with Rolls) ended up late to the party with the V2500. East Hartford had chosen poorly: the original, smaller JT10D prototype is part of the company’s museum collection, having spent years hidden in a potato shed from vengeful C-suiters who wanted it smelted.

The CFM56 did all right.

Other realities of 2015 that nobody would have predicted in 1975: The 737, which Boeing in 1975 considered unworthy of further development, is the company breadwinner. A spooky Pentagon project called Navstar, intended to make Trident nuclear missiles more accurate, guides consumer-level Parrot drones over the static park and helps showgoers find dinner. And one of the European fighters contending over the F-16 replacement market is being displayed here by Airbus. Airbus!

Now fiche-moi la pelouse, gamins!