Acceleration :
Acceleration is a vector quantity that is defined as ❝ rate of change in velocity ❞
And as per the question, the plane can go from 0 miles to 100 miles/hour in 10 seconds that shows rate of change in its velocity. that is :
from 0 miles/hour to 100 miles/hour. hence Acceleration is the quantity being described about the new plane.
[ v = final velocity, u = initial velocity, t = time ]
So, the Acceleration of the new plane is 10 miles/hour²