Carry-on and carrion are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Carry-on is a noun. It means the bag an airline passenger brings on an airplane flight with them. Typically carry-ons, or carryons, have size and weight limitations.
In the phrase carry-on luggage, carry-on is an adjective.
Carrion is a noun. It means the bodies of dead animals out in the wilderness, on sidewalks, or on the side of the road. It can also mean something rotten or vile.
The following story uses both words correctly:
Corinne struggled to find out why her purse or carry-on smelled like carrion. Then she discovered the culprit: a balled up napkin with what looked like egg yolk in it. The other day at the grocery she got a call. When she wasn’t looking, her toddler had dropped on egg at the store, and meaning well, took tissues out of her purse to clean it up, then put the ball of dirty tissues back in her purse. Ugh.