Nautical or statute miles?

Pardon my ignorance folks but …

This afternoon I was reading 263 Sqdn’s Form 540 and 541 where it was mentioned that the “Whirlwind’s operational range was 135 miles”.

My question is:
Would this mean that its range was 135 nautical miles (based on the assumption that air speed is measured in knots, so distance would be in nautical miles), or would it mean that its range was 135 miles (based on miles per hour)

Thank you all in advance for your words of illumination!

Paul