Answer:
N is a population parameter; the computation using an estimate of N is a statistic.
Explanation:
A parameter is a measure of a population. The number of warplanes fielded total is N; this makes it the population. Thus N is a parameter.
A statistics is a measure of a sample. The number computed using an estimate of N would be based on a sample, since it is an estimate of N; this makes it a statistic.