MacBook Air and iPhone 5 won't airdrop!!!!!

I really hope someone can help me. I'm loosing my mind over this.

I can use Airdrop between my iPad Air and MacBook Air - no problem!

I can use Airdrop between my iPad Air and my iPhone 5 - no problems!!

But I cannot for the life of me get my MacBook Air and iPhone 5 to talk!!!

I've done all the usual: and I am completely sure they'll all set up correctly, especially given the above....

Help?