Let's explore both possibilities:
"Y" sound as in "fly":
* Sky-high: Describing something very tall.
* Fly-by-night: Something unreliable or temporary.
* Dry-clean: A method of cleaning clothes without water.
* Skydiving: The sport of jumping from an airplane with a parachute.
* Flycatcher: A type of bird that catches insects in mid-air.
* Butterfly: A colorful insect with wings.
* Skylight: A window in a roof.
* Flyover: A bridge or elevated road that passes over another road.
"Y" sound as in "try":
* Try-out: A test or audition to see if someone is suitable for a job or position.
* Try-on: To put on an item of clothing to see if it fits.
* Merry-go-round: A rotating amusement ride with horses or other animals.
* Merrymaking: Celebrating or having fun.
* Merry-hearted: Happy and cheerful.
* Merry-Christmas: A greeting used during the Christmas season.
Let me know if you had a specific type of compound word in mind, and I'd be happy to provide more examples!