Haha.

I have to agree that I have no idea how'd I explain it to someone who doesn't know what probability means.

Statistically significant means that you can reject the null hypothesis to your assumption with a certain confidence level which is itself a probability. The number of samples is nowhere nearly as weighing in this process as is the randomness of the sampling, the strength of the tested hypothesis, and the required confidence interval, and the ability to find the distribution of the stochastic events.
To claim that from a sample of 100 flights, one cannot draw statistically significant conclusions is mind bogglingly far removed from any mathematical reality .