Flys or Flies? Simple Grammar Rules You Need to Know

If you’re wondering whether to write flys or flies, the correct spelling in standard English is flies. Flys is generally a misspelling when you mean the plural of fly or the third-person singular form of the verb fly.

For example:

• Time flies when you’re having fun.
• The bird flies across the sky.
• She flies to London every summer.
• The plane flies over the mountains.
• There are several flies in the kitchen.

The reason this spelling causes confusion is that many verbs simply take -s in the third-person singular, such as runs or walks. However, fly changes its y to ies when it takes this form.

Flys or Flies: Which Is Correct?

Flies is the correct standard English spelling. Flys is normally incorrect when you mean either the plural noun flies or the verb form flies.

Form	Use	Example
flies	Plural noun	There are two flies on the window.
flies	Third-person singular verb	The bird flies south.
flys	Not the standard spelling for these uses	❌ The bird flys south.

So, if you’re writing “she flys,” “he flys,” “a bird flys,” “time flys,” or “the plane flys,” use flies instead.

The simple rule

When fly becomes a third-person singular verb, the y changes to ie before the final s:

fly → flies

The same spelling pattern appears in other English verbs:

• try → tries
• cry → cries
• carry → carries
• study → studies

This is why flies is correct rather than flys.

What Does Flies Mean?

Flies has two common grammatical uses.

Flies as a verb

Flies is the third-person singular present-tense form of the verb fly.

It describes someone or something moving through the air, traveling by aircraft, or piloting an aircraft.

Examples:

• The eagle flies high above the valley.
• She flies to New York every month.
• He flies a small plane.
• The aircraft flies at a high altitude.
• A bird flies over the lake.

Here, flies is a verb.

Flies as a noun

Flies can also be the plural of fly, referring to the insects.

Examples:

• There are flies around the food.
• I saw several flies near the window.
• The flies disappeared after the door was closed.

Here, flies is a plural noun.

So the same spelling, flies, can have different meanings depending on the sentence.

Why Is Flys Incorrect?

The mistake usually happens because people expect the plural or third-person singular form to be made by simply adding -s.

For many words, that works:

• book → books
• car → cars
• walk → walks
• jump → jumps

But words ending in a consonant followed by y often follow a different spelling pattern.

For fly, the y changes to ie before s:

fly → flies

This applies when fly is used as a verb with a third-person singular subject:

• He flies.
• She flies.
• It flies.
• The plane flies.
• The bird flies.

It also applies to the plural noun:

• one fly
• two flies
• several flies

Therefore, flys isn’t the standard spelling for these meanings.

She Flys or Flies?

The correct form is “she flies.”

Because she is a third-person singular subject, the present-tense verb must be flies.

Correct:

• She flies to Canada every year.
• She flies home on Friday.
• She flies a plane for a living.
• She flies frequently for work.

Incorrect:

• ❌ She flys to Canada every year.
• ❌ She flys home on Friday.
• ❌ She flys a plane for a living.

The same rule applies to he or it:

• He flies to Chicago tomorrow.
• He flies a helicopter.
• The bird flies away.
• The plane flies over the city.

A Bird Flys or Flies?

The correct sentence is:

A bird flies.

Because a bird is singular, the verb fly becomes flies.

Examples:

• A bird flies over the garden.
• The bird flies toward the tree.
• A small bird flies into the room.
• The eagle flies above the mountains.

If the subject is plural, the base form fly is used:

• Birds fly south in winter.
• The birds fly across the lake.
• Many birds fly long distances.

Notice the difference:

• The bird flies.
• The birds fly.

The singular subject takes flies, while the plural subject takes fly.

Flys or Flies Away?

The correct phrase is “flies away.”

For example:

• The bird flies away.
• The butterfly flies away when I get close.
• She flies away tomorrow morning.

The form “flys away” is not standard English.

If the subject is plural, use fly away:

• The birds fly away.
• The butterflies fly away.
• The planes fly away from the storm.

Time Flys or Flies?

The correct expression is:

Time flies.

This is a very common English expression meaning that time seems to pass quickly.

For example:

• Time flies when you’re having fun.
• Time flies when you’re with people you love.
• I can’t believe it’s already October. Time flies!
• How time flies!

The spelling “time flys” is incorrect in standard English.

What does “time flies” mean?

Time flies means that time seems to pass very quickly.

For example, if you haven’t seen a friend for ten years and suddenly realize how long it has been, you might say:

Time flies!

You can also say:

How time flies!

The expression is especially common when talking about childhood, holidays, relationships, school years, or other periods that seem to have passed quickly.

Time Sure Flys or Flies?

The correct phrase is:

Time sure flies.

Here, flies is the third-person singular form of the verb fly.

Examples:

• Time sure flies when you’re having fun.
• Time sure flies when you’re busy.
• Time sure flies. My son is already ten years old.

The phrase “time sure flys” contains the common spelling mistake.

You may also see:

• Time sure does fly.
• Time really flies.
• Time flies so quickly.
• How time flies!

Flys or Flies for a Plane?

Use flies.

When talking about a plane, flies can describe the aircraft moving through the air:

• The plane flies over the ocean.
• The plane flies from Paris to Rome.
• The aircraft flies at a high altitude.

It can also describe what a person does when they travel by air:

• She flies to Paris tomorrow.
• He flies to New York every week.

And flies can describe someone piloting an aircraft:

• He flies a commercial aircraft.
• She flies a helicopter.
• The pilot flies the plane safely.

So these are all correct:

• The plane flies.
• She flies to Boston.
• He flies a plane.

Flys or Flies for Travel?

For travel, use flies.

Examples:

• She flies to Dubai next week.
• He flies home every December.
• My brother flies frequently for work.
• The airline flies to several European cities.

If you’re talking about yourself or another plural subject, use fly:

• I fly to Lahore tomorrow.
• We fly home on Sunday.
• They fly internationally several times a year.

The form depends on the subject:

Subject	Correct form	Example
I	fly	I fly tomorrow.
You	fly	You fly on Friday.
He	flies	He flies on Friday.
She	flies	She flies tomorrow.
It	flies	It flies very high.
We	fly	We fly home tonight.
They	fly	They fly every month.

Flys or Flies Sound

Flies is pronounced /flaɪz/.

A simple pronunciation guide is:

flies = flyz

It has one syllable and rhymes with words such as:

• eyes
• cries
• lies
• tries

The spelling flies can represent the verb flies or the plural noun flies, and the pronunciation is the same in both cases.

For example:

• The bird flies. → /flaɪz/
• There are flies in the room. → /flaɪz/

The final sound is /z/, not /s/.

How Do You Spell Flys or Flies?

The correct spelling is:

F-L-I-E-S → flies

Not:

F-L-Y-S → flys

A useful way to remember it is:

fly → flies

The y changes to ie before the final s.

This spelling applies to both the verb and the plural noun:

• The bird flies.
• Two flies are on the wall.

Is Flys a Word?

Flys is not the standard spelling for the common English uses discussed here. If you mean the plural of fly or the third-person singular form of the verb fly, write flies.

For example:

• ❌ The bird flys.
• ✅ The bird flies.
• ❌ Time flys.
• ✅ Time flies.
• ❌ There are three flys.
• ✅ There are three flies.

You may occasionally encounter Flys in a name, title, brand, username, abbreviation, or another specialized context. That doesn’t make it the standard spelling for the ordinary English forms of fly.

Common Mistakes With Flies

Here are some common sentences that cause confusion.

Incorrect: The bird flys away.

Correct: The bird flies away.

The subject the bird is singular, so the verb is flies.

Incorrect: She flys to London.

Correct: She flies to London.

The third-person singular form of fly is flies.

Incorrect: Time flys so fast.

Correct: Time flies so fast.

The expression uses the verb form flies.

Incorrect: I saw three flys.

Correct: I saw three flies.

The plural of the insect fly is flies.

Incorrect: The plane flys over the city.

Correct: The plane flies over the city.

The singular noun plane requires the third-person singular verb flies.

Flies or Fly: When Should You Use Each Form?

The choice between fly or flies depends mainly on the subject and grammatical structure.

Use “fly” with I, you, we, or they

Examples:

• I fly to New York every year.
• You fly tomorrow.
• We fly home tonight.
• They fly across the country.

Use “flies” with he, she, or it

Examples:

• He flies every week.
• She flies to London tomorrow.
• The bird flies across the lake.
• The plane flies above the clouds.

Use “flies” as the plural of the insect

Examples:

• One fly is on the table.
• Two flies are on the table.
• Several flies entered the room.

So flies has two important uses: it can be a verb or a plural noun.

10 Examples With Flies

Here are natural examples covering the main uses:

• The bird flies over the house.
• She flies to Paris every summer.
• He flies a small aircraft.
• The plane flies above the clouds.
• Time flies when you’re having fun.
• How time flies!
• The butterfly flies from flower to flower.
• A bee flies around the garden.
• There are several flies near the window.
• The airline flies to many international destinations.

Frequently Asked Questions

Is “flys” correct English?

Usually, no. For the ordinary verb form or plural noun, the standard spelling is flies.

Is it “time flys” or “time flies”?

The correct phrase is “time flies.” It means that time seems to pass quickly.

Is it “she flys” or “she flies”?

The correct form is “she flies.” Flies is the third-person singular present-tense form of fly.

Is it “he flys” or “he flies”?

Use “he flies.” For example: He flies to New York every month.

Is it “the bird flys” or “the bird flies”?

Use “the bird flies.” A singular subject such as the bird takes flies in the simple present.

Is it “the plane flys” or “the plane flies”?

The correct sentence is “the plane flies.” For example: The plane flies over the mountains.

Is “flys” a word?

Flys is not the standard spelling for the common plural or verb forms of fly. In ordinary English, use flies.

How do you spell “flies”?

It is spelled F-L-I-E-S. The spelling changes from fly to flies.

How do you pronounce “flies”?

Flies is pronounced /flaɪz/, approximately “flyz.” It has one syllable.

What is the plural of “fly”?

The plural of the insect fly is flies.

Conclusion

The correct spelling is flies, not flys, when you’re using the standard English plural of fly or the third-person singular form of the verb fly.

Remember these two main uses:

• The bird flies. — flies is a verb.
• There are several flies. — flies is a plural noun.

The same rule explains common expressions such as “time flies” or sentences such as “she flies to London.”

A simple memory trick is:

fly → flies

Once you remember that the y changes to ie, forms such as she flies, he flies, the bird flies, the plane flies, or time flies become much easier to spell correctly.