What is certain is that there was a Formula 2 race on the Innsbruck airfield in 1960.
The records show a circuit length of 1.7 kilometers and lap times of a little under 60 seconds, which would tend to sound about right.
Okay.... but now look at this.....
The first picture is the circuit plan that is shown for that race:
This is a recent picture of the airfield with what seems to be the correct line of the circuit marked in red:
The evidence appears to me to be hard to refute.
However, the length of the circuit as marked in red is 1.8 MILES, well over 3 kilometers!
So, I'm afraid I am very confused.