Doing something "on the fly" means to do something on the spur of the moment without prior planning or consideration.
"Spontaneous" means doing something without planning or forethought, often on impulse.
"In slang, 'on the fly' means doing something quickly or spontaneously without much preparation or planning."
He spoke off the cuff means to speak without planning what you want to say. It means to just say what comes to your mind first. It means to say something without thinking about it. It means to speak without preparing for it.
"wing it" means to do something without much preparation or planning. So "you will just wing it" suggests that you will do something spontaneously or improvisationally without a solid plan in place.
The word you're looking for is "spontaneous." It means something that occurs naturally or without external influence.
it means that they wont do anything without providence
"Impromptu" means something done without preparation or planning. It is typically used to describe a performance or speech that is spontaneous or unrehearsed.
it means to be ready for something before it happens.
"All year round" means that something happens or is available throughout the entire year, without being restricted to a specific season or time period. It indicates that something is continuously ongoing without interruption.
it means to happen in time(0.0)
Spontaneous means without planning. A spontaneous visit to the zoo is one you thought of at the last minute out of nowhere. Spontaneous combustion is when something catches fire without apparent reason, just out of nowhere.