How do I read a 2005 floppy disk on MacBook Air?

This may not be possible.

Your tag line says that you have a 13" MacBook Air running macOS 15.3 (Sequoia). The very oldest one it could be is an Intel-based MacBook Air (Retina, 13-inch, 2020), which is not capable of running any version of macOS that's earlier than macOS 10.15.3.

If this is a 400 KB or 800 KB floppy disk, there is no way for you to read it. Old Macs squeezed 400 KB and 800 KB onto discs that, on PCs, only held 360 KB or 720 KB. But only built-in floppy drives on those old Macs … or Apple-brand external floppy drives designed for those old Macs – can read the discs. No USB floppy disc drive is able to read those discs, and the operating system on your Mac is new enough that it wouldn't understand the filesystems (MFS, HFS) on those discs.

If this is a 1.44 MB floppy disc, it depends on how it is formatted. You can get USB floppy drives, and connect them to your Mac (with the aid of USB-C to USB-A adapters, if needed). However, Catalina dropped support for HFS (no "+"), which means that if that floppy disc is a 1.44 MB HFS floppy disc, even getting a USB floppy drive for your Mac won't let you read it.

If the disc is a 1.44 MB PC-formatted floppy disc, then a USB floppy drive might let you read it – assuming that the data on that disc is still intact after all of these years.