Aioli has garnered a reputation for itself as a fancier version of mayo, but what exactly makes it the more glamorous relative of classic mayonnaise? Garlic.
A combination of the words for garlic "ai" and oil, in Catalan, Valencian and Provençal, aioli is a Mediterranean creation that includes lots and lots of garlic. More specifically, it's an emulsion made from olive oil with smashed garlic. Because it doesn't have any binders (such as eggs), it is very finicky and can fall out of emulsion (the oil separates back out) easily. This is the reason behind why so many restaurants and home cooks alike switch over to using mayonnaise as a base, and add a heavy hand of garlic to give it a similar flavour to a real aioli.
Whether you take the time to create an emulsion from scratch with olive oil and a healthy helping of garlic or just want to throw some seasonings and garlic into mayo, it will make a great sauce, spread or dip.