Definition of pigs might (or can) fly in English:

pigs might (or can) fly

phrase

British
  • Used ironically to express disbelief.

    ‘‘Maybe he's trying to change.’ ‘And maybe pigs can fly.’’
    • ‘Today was exactly like yesterday and to think tomorrow will be any different is the hope that pigs might fly.’
    • ‘Shrugging his shoulder, he replied easily, ‘I'll save you the day pigs can fly.’’
    • ‘‘And pigs can fly,’ Stevens said sarcastically.’
    • ‘However, the heavily disguised Greenpeace Mercedes Benz shows just when they think the world will stop polluting itself - when pigs might fly!’
    • ‘The Truth might be there - undeniable and incontrovertible - but there'll still be people who'll say the world is flat, that the moon is made of green cheese and that pigs can fly.’
    • ‘As the Police are to get their 76 per cent increase, maybe we will see a local bobby walking the beat and incidents such as these would be totally avoidable, then again pigs might fly.’
    • ‘She rolled her eyes, ‘Right and pigs can fly.’
    • ‘Ryan looked at her incredulously ‘I'll let you and your companion go when pigs can fly!’’
    • ‘Well, if people believe that, they believe that pigs can fly.’
    • ‘Well, that was the theory, but they forgot that pigs might fly too.’