"Seeing how it flies" is a phrase commonly used to describe the act of experimenting or testing something to see how it performs. There are several synonyms that can be used in place of this phrase to convey the same meaning. For example, "trial and error" is another common expression used to describe the process of experimenting to determine the best approach. Other synonyms might include "testing the waters," "putting it to the test," or "giving it a try." Ultimately, these phrases all communicate the idea of trying something out with an open mind to see how it works in practice.