What does it mean in slang on the fly?

"On the fly" in slang means doing something quickly, spontaneously, or without much preparation. It implies a sense of improvisation and urgency.

Here are some examples of how "on the fly" is used:

* "I had to make a decision on the fly." This means the decision was made quickly and without much time to consider the options.

* "We threw together a meal on the fly." This implies the meal was made quickly and with whatever ingredients were available.

* "He's a great improviser, always coming up with ideas on the fly." This means he is able to think of solutions quickly and without prior planning.

The phrase "on the fly" is often used in situations where something unexpected happens and a quick response is needed. It can also be used to describe someone who is good at thinking on their feet.