[scoopertrooper]

That calculation rests on the assumption that Concord was a necessary step toward Airbus. Given that the Airbus A300 actually entered service prior to the Concord, it seems to me that Concord was not a necessary precondition.

Granted, the Concord was the first aircraft to have fly-by-wire. However, it used an entirely different technology (analogue fly-by-wire) to the Airbus A320 (digital) and preceded it by a decade.

Were there some lessons learned from the Concord that carried over to the Airbus A320? Maybe? However, the causal relation you've conjectured seems quite tenuous.

[willyt]

Well it set a precedent for Cross-European collaboration and presumably a whole bunch of engineers from Britain and France all started talking to each other sharing ideas, learning each other’s language and cultural differences in the early 1960’s. The development of the A300 was started about 8 years after France and Britain merged their SST projects, the bulk of the development of the A300 was done in the 70’s. The engineers that worked on the Concorde programme would have started to become available to begin work on the A320 in the late 70’s/early 80’s. Also there is at least one digital computer in Concorde, I think it was the engine/intake controller that prevents the unstart problems that the Blackbird suffered from but I don’t remember TBH.

[scoopertrooper]

> Well it set a precedent for Cross-European collaboration and presumably a whole bunch of engineers from Britain and France all started talking to each other sharing ideas, learning each other’s language and cultural differences in the early 1960’s.

Maybe. Hard to say. But, if the 'Concord' was a project to build a wide body subsonic passenger jet, then the outcome would have been much the same, with the exception of a genuinely useful aircraft being produced.

> The engineers that worked on the Concorde programme would have started to become available to begin work on the A320 in the late 70’s/early 80’s.

Again, perhaps. Maybe, they were employed more on military jets? Who knows? European aeronautical engineers knew how to build passenger jets before Concord and not every European aeronautical engineer worked on Concord.

> Also there is at least one digital computer in Concorde

Probably, they had pocket calculators before that bird took off for its first flight. I don't really see how that matters.

Generally, the problem with these X is justified because it preceded Y arguments is that they overlook the fact we could have directly applied our efforts toward reaching Y.