Preheat your air fryer to 400°F (200°C) for about 5 minutes.
Rinse the asparagus spears and pat them dry.
Trim the bottom ends of the asparagus, about 1-2 inches, depending on the toughness.
Place the trimmed asparagus in a bowl. Drizzle with olive oil, then season with salt and pepper. Toss until all the spears are evenly coated.
Arrange the asparagus in the air fryer basket in a single layer. It's okay if they overlap a little, but it's best if air can circulate around them.
Air fry for 7-10 minutes, depending on how thick your asparagus spears are. Shake the basket or turn the asparagus halfway through cooking to ensure even cooking.
Check the asparagus for doneness at around 7 minutes. They should be tender and slightly crisp.
Once done, you can squeeze some fresh lemon juice over the asparagus if you'd like.
Serve immediately for the best taste and texture.
Notes
A good sprinkle of fresh Parmesan over the asparagus while they are still hot is really good too.
The lemon is option but I think it adds a nice brightness to the asparagus. That being said, my kids don't like it at all (but love asparagus without the lemon) so I'll often just drizzle a little on my own serving.
Asparagus is a spring vegetable and will be the best tasting that time of the year.