In the context of the answer, an "essay" would be one post that discusses both possible answers, including how they relate and differ and why. This is certainly acceptable on the site. Depending on the topic, it doesn't have to be long, but we have some extremely long answers already. Note that especially with longer answers it's important to include formatting and clear structure to help readers navigate and stay engaged.
Specifically on Aviation.SE, we don't typically see cases where a user posts two answers. In most cases, one answer could discuss the multiple angles. If a user wants to post two completely unrelated and different answers to the same question, it's a sign the question could be too opinion-based to be on topic. People may also see multiple answers by one user as a cheap attempt to gain reputation, so both answers should be clear in how they are valid answers and show a good amount of effort.