Correct spelling, explanation: both flyer and flier are accepted spellings, and both are considered correct. However, there is a slight difference in usage. In American English, flier is more commonly used to refer to a handbill or a promotional piece of paper advertising an event or product. In British English, flyer is often used to describe a person or thing that flies, such as an aviator or an airborne object. However, the distinction is not strict, and the two spellings are often used interchangeably.

Definition of flyer:
1. Noun, a person or thing that flies, especially in a particular way
The skilled pilot maneuvered the fighter jet with the precision of a seasoned flyer.
The majestic eagle soared through the sky, showcasing its prowess as a natural flyer.
2. Noun, a small handbill advertising an event or product
As I walked through the crowded street, a friendly promoter handed me a colorful flyer announcing the upcoming music festival.
The local bakery distributed flyers with enticing images of their freshly baked goods to attract customers to their grand opening event.

Collocations with flyer:
Some most commonly used collocations include:
1. Promotional flyer: a handbill or document designed for promotional purposes.
The company distributed promotional flyers to announce the launch of their new product.
2. Event flyer: a flyer specifically created to advertise an upcoming event.
She designed an eye-catching event flyer to attract attendees to the charity fundraiser.
3. Travel flyer: a promotional document advertising travel deals or destinations.
We picked up a travel flyer at the tourism office, showcasing amazing vacation packages.
4. Club flyer: a flyer promoting events or specials at a nightclub or similar venue.
The club handed out colorful club flyers to passersby, inviting them to the weekend party.

Correct spelling, explanation: both flier and flyer are correct spellings, and the choice between them often depends on regional variations and personal preference. However, it’s worth noting that flier is more commonly used in American English, while flyer is sometimes favored in British English. In practice, you can choose either spelling based on your preference or the conventions of the region you are writing for. Many style guides and dictionaries accept both forms.