Beofre you run off and get a floppy drive for your MacBook, check one thing.

Boot the Classic with the key combination, and then stick a floppy in the drive. If it pops up a little message about the disk being unreadable, go ahead and format the bugger. If it does that and you see the disk pop up on the desktop, then you know that you're floppy drive is working (this is always a good thing to check, because these seem to die off regularly).

Once you have done that, open up the "Boot Disk" (the little floppy icon with a chip on it) and drag the System Folder that you'll find in there onto the floppy that you just formatted. After it's done copying, shut down the Classic. It should spit the floppy out for you. Stick it back in and then flip the machine on. If it boots off the floppy like it should, then this confirms that you have a fully functional floppy drive and should be alright to go ahead and get one for your MacBook so they can talk.

Not only that, but this'll give you the illusive bootable floppy