Air drop does not work on my MacBook Pro. It works on my iPhone and iPad, even thought air drop is enabled on all units. Why?

How old and what OS version is your macbook pro? It requires a Mac 2012 or later

https://support.apple.com/en-us/HT203106

Also note: my 2012 MBP had airdrop, but possibly because it was at the "minimum required" level, it rarely worked. Maybe 20% of the time it actually did.

Well, then it should - but, I have found it to be "temperamental". Sometimes it works and sometimes it won't.