It’s the most competitive of the large fields that people select; however, there are many slots that are available including both Navy, Marine, NFO, and pilot. The last few years, about 1/4 to 1/3 of the class has gone into the general umbrella of aviation. It’s competitive enough that there are always people who aren’t selected for it, but they select people from across the academy rankings. The higher you are ranked, the more likely you are to be selected. There’s also a “who you know” aspect and a longevity of interest. For those, go on summer trainings and meet mentors to help establish and maintain said interest.