Say it like this
- We made the change on the fly when we saw the issue
- Let's fix this on the fly before the release
- We're generating the report on the fly as users request it
Use it at work
Explaining code
- The thumbnails are generated on the fly.
- We calculate prices on the fly, not in advance.
In meetings
- I'm making this up on the fly, so let's check later.
- We changed the plan on the fly.
Pushing back
- Let's not design this on the fly. I'll write a doc.
- Changes made on the fly are hard to track.
Don't say this
On the fly is an adverbial phrase describing how something is done, not a verb itself. It must accompany an action verb.
Practice
Try it
4 quick exercises
1. Your deployment is in 10 minutes and you need to fix a critical bug. How do you describe what you are doing?
2. During the customer demo, the stakeholder requested a feature change, so we modified the interface _______ to show them how it would look.
3. Which sentence uses on the fly incorrectly?
4. Rewrite this in natural tech English using on the fly: We did not plan to change the API format, but we made the change without waiting because the client needed it immediately.
Say it out loud
Phrase 1 of 3
"We made the change on the fly when we saw the issue"
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More about on the fly
Real examples(3)
- in a standup
"We discovered the performance issue yesterday, so we optimized the query on the fly and deployed the fix."
- in a code review
"Instead of waiting for the next sprint, the team decided to refactor the authentication module on the fly."
- in a client meeting
"The client asked for a different color scheme, so we updated the UI on the fly to show them the new design."
More mistakes(2)
Handle with care. Do not use as a verb on its own (say 'do on the fly' not 'on the fly it'). It describes the manner of an action, not the action itself.
- ✕On the flying, we made the adjustments.✓On the fly, we made the adjustments.
The phrase is always 'on the fly' (not 'on the flying'). It is a fixed expression.
- ✕We will plan everything on the fly.✓We will make decisions on the fly, but we should still have a basic plan.
On the fly suggests rapid response to immediate needs, not the absence of all planning. Using it for major planning can sound unprofessional.
Other forms(2)
- on the fly phrase
"We adjusted the server configuration on the fly when the error occurred."
- on the fly adverbial modifier
"She generated the report on the fly using the new data."
Often used with(4)
- fix / adjust / modify on the fly · Most common pairing; describes making quick technical changes
- decide / pivot on the fly · Used when strategy or direction changes suddenly
- generate / compile on the fly · Describes creating something in real time during execution
- handle on the fly · Dealing with an issue as it arises without preparation
Similar words(4)
- in real time · Similar meaning but emphasizes simultaneity; on the fly emphasizes lack of planning
- on the spot · More informal and broader; on the fly is more specific to spontaneous changes
- ad hoc · More formal; on the fly is more conversational and common in tech culture
- dynamically · More technical term used in programming contexts; on the fly is more general workplace language
Opposites(3)
- planned in advance
- pre-configured
- scheduled
Questions(5)
- What does on the fly mean in software engineering?
- In software engineering, on the fly means making changes or decisions in real time without advance planning. For example, developers might modify code on the fly during debugging, or a team might adjust their deployment strategy on the fly when unexpected issues arise. It emphasizes speed and immediate response to current conditions.
- How do you use on the fly in a sentence at work?
- Use on the fly as an adverbial phrase that describes how an action is performed. For example: We optimized the query on the fly when we saw the performance issue. We generated the report on the fly using live data. Always pair it with an action verb (fix, adjust, modify, generate, decide, etc.). Do not try to use it as a verb by itself.
- Is on the fly formal or informal?
- On the fly is neutral in formality. It is casual enough for team standups and chat messages, but it is also acceptable in formal meetings, presentations, and documentation. It is widely used in professional tech environments and does not sound unprofessional, though in very formal writing you might prefer alternatives like 'in real time' or 'dynamically.'
- Can you plan things on the fly?
- Not really. On the fly implies lack of planning—it means doing something immediately without advance preparation. If you are planning ahead, you are not doing it on the fly. However, you can make adjustments or pivots to your plans on the fly.
- Is on the fly used only in tech?
- No, on the fly is used across many industries (finance, media, manufacturing). However, it is very common in tech culture, especially in agile development environments where rapid iteration and quick decision-making are normal.
