The phrase "by seat of pants" refers to a haphazard or improvised approach to a situation. Its antonyms include "methodical," "systematic," "organized," and "planned." A methodical approach involves careful planning, order, and attention to detail. A systematic approach involves a step-by-step process, following guidelines or procedures. An organized approach involves efficient time management, setting priorities, and making use of resources. A planned approach involves forethought and preparation, setting goals, and creating strategies to achieve them. Unlike the improvisational approach of "by seat of pants," these antonyms all suggest a deliberate and structured approach to a task or project.