I already solved my Airdrop problem 🙂. You may reset the PRAM as others would suggest. But, this is what I did: reset the network settings of your iOS device. If your Mac would normally recognize other Macs, even the old models that are capable of Airdrop, but not iOS devices, reset network settings of your iOS device. Here's how:
1. Go to Settings>General.
2. Go to General>Reset.
3. Within the Reset section, choose Reset Network Settings.
4. Your iDevice will reset, but just quickly; showing the Apple logo and a loading bar.
5. Let it load then turn on Wi-Fi (you may connect to a Wi-Fi router by re-inputting the password since settings were reset to factory settings) and Bluetooth; set visibility to Everyone.
6. Turn on Wi-Fi and Bluetooth on your Mac..
7. Go to Finder>Airdrop, or command+shift+R.
8. Wait until for your iOS device gets recognized.
*Airdrop can work as long as Wi-Fi and Bluetooth are activated regardless if you're connected to the internet; Airdrop doesn't need internet connection
*Macbook Air 13" mid-2013, OS X El Capitan 10.11.2
*iPhone 5C, iOS 9.2