Flys By or Flies By: Which Is Correct? Meaning, Grammar Rules, and Examples

Many English learners wonder whether “flys by” or “flies by” is the correct spelling when describing something moving quickly through the air or when time passes quickly. This confusion happens because English verbs often change spelling when adding “-s” in the third-person singular form.

The correct choice depends on the basic spelling rule for verbs ending in consonants and the letter “y.” In this guide, you will learn the difference between flys by or flies by, why one spelling is correct, how to use it properly, and how to avoid this common grammar mistake.

(Quick Answer) Flys By or Flies By

**“Flies by” is the correct spelling, while “flys by” is incorrect in standard English. The verb “fly” changes to “flies” when used with he, she, or it because verbs ending in a consonant + y change the “y” to “ies.” Example: “Time flies by when you are having fun.”

Flys By or Flies By: Quick Comparison Table

Category	Flys By	Flies By
Correct Word	Incorrect	Correct
Meaning	No standard meaning in English	Moves through the air or passes quickly
Definition	Incorrect spelling of “flies by”	Third-person singular form of “fly” + “by”
Part of Speech	None (misspelled verb form)	Verb phrase
Grammar Rule	Does not follow spelling rules	Follows consonant + y spelling rule
Correct Usage	Never used in standard English	Used with he, she, it, or singular nouns
Incorrect Usage Example	“The bird flys by the window.”	“The bird flies by the window.”
Pronunciation	Not applicable	/flaɪz baɪ/
Common Mistake	Adding “s” directly to “fly”	Correctly changing “y” to “ies”
Memory Tip	“Flys” looks similar but is wrong	“Fly + ies = flies”
Example	“The plane flys by every morning.” ❌	“The plane flies by every morning.” ✅

Meaning of Each Word

What Does “Flys By” Mean?

“Flys by” is not considered a correct English word combination. It is a common spelling mistake caused by misunderstanding how verbs ending in “y” change in the third-person singular form.

Some writers incorrectly add only “s” to “fly,” creating “flys.” However, English grammar requires a spelling change in this situation.

Incorrect examples:

• The eagle flys by the mountain.
• The airplane flys by my house every day.
• Time flys by so quickly.

Correct versions:

• The eagle flies by the mountain.
• The airplane flies by my house every day.
• Time flies by so quickly.

The incorrect form may appear in informal online writing, but it should be avoided in professional, academic, and formal communication.

What Does “Flies By” Mean?

“Flies by” is the correct phrase in English. It comes from the verb “fly” and the word “by.”

It has two main meanings:

1. Something Moving Through the Air

When something physically moves through the air, “flies by” describes its movement.

Examples:

• The bird flies by the open window.
• A butterfly flies by the garden flowers.
• The helicopter flies by the tall buildings.

2. Time Passing Quickly

“Flies by” is also used as an expression meaning that time passes very quickly.

Examples:

• The weekend flies by when you are busy.
• Childhood flies by faster than people expect.
• The year flies by when you have exciting goals.

This figurative meaning is extremely common in everyday English.

Key Differences Between Flys By and Flies By

The main difference is simple:

• Flies by is correct English.
• Flys by is a spelling mistake.

Other important differences include:

• “Flies” follows the standard verb spelling rule for words ending in consonant + y.
• “Flies by” can describe physical movement or the quick passing of time.
• “Flys by” has no accepted meaning in modern English.
• “Flies” is used with singular subjects such as he, she, it, a bird, a plane, or time.
• The spelling changes because English does not usually keep the “y” after adding “-s” to these verbs.

Examples:

Correct:

• She flies by plane every month.
• The bird flies by the lake.
• Time flies by during vacations.

Incorrect:

• She flys by plane every month.
• The bird flys by the lake.
• Time flys by during vacations.

Grammar Rules Behind “Flies”

The spelling of “flies” follows an important English grammar rule.

When a verb ends in:

consonant + y

the “y” changes to “ies” when adding “-s” for he, she, or it.

Formula:

Verb ending in consonant + y → change y to ies

Examples:

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

Examples in sentences:

• He flies to New York every week.
• She tries her best.
• The baby cries loudly.
• He studies English grammar.

However, if a verb ends in:

vowel + y

the “y” stays the same.

Examples:

• play → plays
• enjoy → enjoys
• stay → stays
• buy → buys

Examples:

• She plays tennis.
• He enjoys reading.
• The child stays home.

“Fly” follows the consonant + y rule because the letter before “y” is “l,” a consonant.

When to Use “Flies By”

Academic Writing

In academic writing, use “flies by” when discussing movement, natural processes, or the passage of time.

Examples:

• The bird flies by the research station during migration.
• Historical periods seem to pass quickly, and time flies by.

Avoid “flys by” because it is grammatically incorrect.

Professional Writing

Professional emails, reports, and documents require correct spelling.

Examples:

• The aircraft flies by the testing area during the inspection.
• Another year flies by as the company continues to grow.

Using “flys” may make writing appear careless.

Formal English

Formal English always requires the correct form:

• The plane flies by the airport daily.
• Time flies by during important projects.

Informal English

Even in casual conversations, “flies by” is the correct choice.

Examples:

• Wow, this month flies by!
• Time flies by when you are having fun.

Business Writing and Emails

Business communication often uses phrases about time.

Examples:

• The first quarter flies by quickly.
• It feels like the deadline flies by every year.

Daily Conversation

Native speakers commonly use “flies by” in everyday speech.

Examples:

• Your vacation will fly by.
• The day flies by when you are working.

Common Mistakes With “Flys By”

Why People Confuse Them

People often make this mistake because many verbs simply add “s” in the third-person singular form.

Examples:

• walk → walks
• run → runs
• jump → jumps

Because of this pattern, writers may incorrectly assume:

• fly → flys

However, verbs ending in consonant + y follow a different rule.

Incorrect and Correct Examples

Incorrect:

• The bird flys across the sky.

Correct:

• The bird flies across the sky.

Incorrect:

• Time flys by during summer.

Correct:

• Time flies by during summer.

Incorrect:

• She flys to another country often.

Correct:

• She flies to another country often.

Tips to Avoid This Mistake

• Remember that “fly” changes to “flies.”
• Look at the letter before “y.”
• If it is a consonant, change “y” to “ies.”
• Practice similar verbs like “try” and “study.”
• Do not simply add “s” to every verb.

Original Examples of “Flies By”

1. The small plane flies by the coastline every afternoon.
2. The eagle flies by the mountain peak during its search for food.
3. Time flies by when students enjoy their summer break.
4. The first year of college flies by faster than many students expect.
5. The company’s anniversary flies by as employees celebrate its success.
6. The colorful kite flies by the children playing in the park.
7. She flies by helicopter when she needs to reach remote locations.
8. The morning flies by because everyone is busy preparing for work.
9. The bird flies by the window before disappearing into the trees.
10. The meeting flies by because the discussion is interesting.
11. The documentary shows how a spacecraft flies by distant planets.
12. The weekend flies by when families spend time together.
13. The journalist writes that another decade flies by quickly.
14. The butterfly flies by the flowers in the backyard.
15. The training program flies by because the lessons are engaging.
16. The aircraft flies by the airport during the demonstration.
17. The school year flies by with many memorable events.
18. The moment flies by before anyone realizes it.

Memory Trick for “Flies By”

Use this simple trick:

Fly has a “why” change.

When “fly” becomes “he, she, or it flies,” the “y” changes into “ies.”

Remember:

Fly → Flies

Just like:

• Try → Tries
• Cry → Cries
• Study → Studies

Never write “flys” in standard English.

Mini Quiz

1. Which sentence is correct?

A. The bird flys over the lake.
B. The bird flies over the lake.
C. The bird fly over the lake.

Answer: B. The bird flies over the lake.

2. Choose the correct spelling.

A. Time flys by quickly.
B. Time flies by quickly.
C. Time flyes by quickly.

Answer: B. Time flies by quickly.

3. Why does “fly” become “flies”?

A. Because all verbs add “ies”
B. Because verbs ending in consonant + y change y to ies
C. Because “flys” is old English

Answer: B. Because verbs ending in consonant + y change y to ies.

4. Which word is incorrect?

A. Tries
B. Flies
C. Flys

Answer: C. Flys

5. Complete the sentence:

“The airplane  across the sky.”

A. flys
B. flies
C. flyes

Answer: B. Flies

Frequently Asked Questions

Is “flys by” a word?

No, “flys by” is not a correct English phrase. It is a common spelling mistake. The correct form is “flies by,” which follows the rule that verbs ending in consonant + y change the “y” to “ies” when used with he, she, or it.

Why is “flies by” correct but “flys by” wrong?

“Flies by” is correct because the verb “fly” ends with a consonant followed by “y.” When adding “-s” for third-person singular subjects, English changes the ending from “y” to “ies.” Therefore, “fly” becomes “flies,” not “flys.”

Does “flies by” only talk about flying?

No. “Flies by” has both a literal and figurative meaning. It can describe something moving through the air, such as a bird or airplane. It can also describe time passing quickly, such as “The year flies by.”

Is “flies by” used in American and British English?

Yes. Both American and British English use “flies by” in the same way. The spelling and grammar rule are identical in both varieties of English.

What is the difference between “flies” and “fly”?

“Fly” is the base form of the verb, while “flies” is used with singular third-person subjects. For example, “Birds fly” is correct, but “The bird flies” is correct because the subject is singular.

How can I remember the correct spelling of “flies”?

Remember that verbs ending in consonant + y change the ending to “ies.” Since “fly” follows this rule, the correct spelling is “flies.” Think of similar examples like “try becomes tries.”

Key Takeaways

• “Flies by” is the correct spelling.
• “Flys by” is an incorrect spelling and should not be used.
• “Flies” is the third-person singular form of “fly.”
• The spelling rule changes consonant + y endings into “ies.”
• “Flies by” can describe movement through the air.
• “Flies by” can also describe time passing quickly.
• American and British English use the same spelling.
• Remember: fly → flies, not flys.

Conclusion

Understanding the difference between flys by or flies by helps you avoid one of the most common English spelling mistakes. The correct phrase is always “flies by” because the verb “fly” follows the consonant + y spelling rule. Whether you are describing a bird moving through the sky or saying that time passes quickly, use “flies by” for accurate and natural English.