Knots are typically used for aviation. Also different planes have their own optimal speeds for efficiency that the airlines aim for so if you know the airframe you can derive what they are most likely targeting. You can also compare the value to the filed flight plan and see if it is similar.
Knots are used for aviation, but this data looks like it's being consumed by the in-flight UI, and most _people_ are not familiar with knots in terms of speed. Indeed, using the UI shows MPH vs. knots. My money is this speed being mph.
