English is full of tricky spelling choices, and one of the most common confusions is Flys or Flies You’ve probably seen both forms used, maybe in casual writing, social media posts, or even by students in essays. But which spelling is actually correct? And when should you use flies? Let’s clear up the confusion with grammar rules, real-life examples, and easy memory tricks.
This guide will cover:
- The correct spelling: flies or flys
- Why the mistake happens so often
- Grammar rules for pluralizing words ending in -y
- How flies works as both a noun and a verb
- Idioms like time flies
- Usage tables, examples, and memory tricks
By the end, you’ll never second-guess this spelling again.
Which Is Correct: Flies or Flys?
The short answer: “flies” is correct, “flys” is a misspelling.
- Flies is the plural noun of “fly” (the insect).
- Flies is also the third-person singular verb of “fly.”
- Flys isn’t recognized in modern English, except in rare historical or brand-name cases (like “Flys Jeans”).
Example:
- Correct: The bird flies across the sky.
- Correct: The picnic was ruined by a swarm of flies.
- Incorrect: The boy flys his kite.
What Is the Plural of Fly?
Like many English words ending in -y, the plural follows a specific spelling rule:
- If a word ends in consonant + y, change -y to -ies.
- If a word ends in vowel + y, just add -s.
| Singular | Correct Plural | Wrong Plural |
| Fly | Flies | Flys |
| Baby | Babies | Babys |
| City | Cities | Citys |
| Toy | Toys | (correct as is) |
So, the correct plural of fly (insect) is flies.
When to Use “Flies”
Flies works as both a noun and a verb.
As a Noun
Refers to insects or sometimes trousers (British English).
- There are flies buzzing around the garbage.
- He zipped up his trousers; the flies were stuck.
As a Verb
The third-person singular form of fly.
- She flies to New York tomorrow.
- The eagle flies over the mountains.
The Common Confusion: Why “Flys” Is a Mistake
People often write flys because:
- It “looks” like a regular plural (just adding “-s”).
- They forget the -y → -ies rule.
- Spellcheck sometimes doesn’t correct it in informal apps.
Remember: 99% of the time, “flys” is wrong.
Examples of “Flies” Used in Sentences
To get a better sense of its versatility, let’s look at some examples:
- As a noun (insect):
- Flies swarmed the picnic table.
- Houseflies are common pests in summer.
- Flies swarmed the picnic table.
- As a verb (action):
- He flies to Mexico every year with his family.
- The baseball flies over the fence during the game.
- She flies slowly, like a bird gliding in the sky.
- He flies to Mexico every year with his family.
Time Flies or Time Flys?
You’ve likely heard the idiom “time flies.” It means time passes quickly, especially when you’re enjoying yourself.
- Correct: Time flies when you’re having fun.
- Incorrect: Time flys when you’re having fun.
This idiom has been around for centuries, and you’ll even find it in Shakespeare:
“O, how this spring of love resembleth the uncertain glory of an April day; which now shows all the beauty of the sun, and by and by a cloud takes all away.” – Shakespeare (Two Gentlemen of Verona)
Historical Context: Was “Flys” Ever Correct?
Yes—sort of. In 19th-century England, “flys” sometimes referred to a type of horse-drawn carriage. Writers like Charles Dickens used it in novels. But today, this spelling is obsolete.
- They hailed a flys to take them to the theatre. (Old usage)
In modern English: flies is the only acceptable form.
Synonyms and Related Words
| Word | Meaning | Example |
| Flies | Insects / moves in air | The plane flies fast. |
| Bugs | Small insects | Bugs crawl on the wall. |
| Mosquitoes | Biting insects | Mosquitoes buzz at night. |
| Soars | Rises/fly high | The eagle soars above the gorge. |
| Glides | Smooth flying | The bird glides slowly. |
Phrases and Idioms with “Flies”
- Time flies – time passes quickly
- Flies in the ointment – small problems ruining something
- Let flies land where they may – accept things as they happen
- Flies off the handle – gets angry suddenly
Trick to Remember the Difference
Here’s a simple mnemonic:
- Words ending in -y after a consonant → replace y with ies.
- Think: a baby has babies, a fly has flies.
Or use this rhyme:
“If a word ends with y and a consonant before,
Change the y to i and add -es once more.”
Writing It Right: Famous Uses of “Flies”
Literature often uses flies metaphorically:
- Tolkien in The Children of Húrin: “Flies buzzed over the corpses of battle.”
- Melville in Moby-Dick: “The flies hovered around the whale oil.”
- Neil Gaiman in American Gods: “Flies swarmed over forgotten offerings.”
Flys or Flies | Correct Spelling & Examples
Let’s quickly compare correct and incorrect spellings:
| Word | Correct Usage | Incorrect Usage |
| Flies | The bird flies high. | The bird flys high. |
| Flies | There are many flies near the window. | There are many flys near the window. |
| Time flies | Time flies when you’re at the beach. | Time flys when you’re at the beach. |
Conclusion: Flys Isn’t a Real Word, But Flies Is
To sum up:
- Flies is the only correct spelling in modern English.
- Use it for both the plural noun and verb form.
- Flys is an outdated or misspelled form.
If you ever doubt, remember: flies are correct, flys is a mistake.
And as the saying goes—time flies, so write it right.
FAQs About “Flys” vs. “Flies”
Q1: Is “flys” ever correct?
A: Only in rare historical contexts (like “carriage flys”). In modern English, it’s always wrong.
Q2: What is the plural of “fly”?
A: The plural is flies, following the -y to -ies spelling rule.
Q3: Can “flies” mean something other than insects?
A: Yes. It can mean movement in the air (The bird flies), or even the zipper on pants (He zipped his flies).
Q4: Why do people misspell it as “flys”?
A: Because it feels like a natural plural. But the rule changes y → ies.
Q5: What does “time flies” mean?
A: It’s an idiom meaning time passes quickly, especially when life is enjoyable.
