Definition of fly (or drive) by the seat of one's pants in English:

fly (or drive) by the seat of one's pants

phrase

informal
  • Rely on instinct rather than logic or knowledge.

    ‘I was flying by the seat of my pants because I'd never managed anybody before’
    • ‘Be prepared and don't fly by the seat of your pants.’
    • ‘Many students in the WPI sections I've taught seemed to be flying by the seat of their pants all semester.’
    • ‘After finding fame and success you can't just fly by the seat of your pants (when it comes to creativity).’
    • ‘Well, ‘something came up’ and they didn't show up, so I was stuck with teaching it, trying to fly by the seat of my pants.’
    • ‘Sometimes I feel as if I fly by the seat of my pants when I'm trying to write a chapter.’